Recording medium, tape drive, and method for identifying type of recording medium

ABSTRACT

When a memory in cassette (MIC) in a loaded tape cassette can successfully be accessed, an MIC type stored in the MIC is detected to judge a data format the tape cassette has. To this end, the tape cassette is adapted such that the data format or the loaded tape cassette can be identified without detecting an identification hole formed in the tape cassette. Thus, it is possible to easily accommodate any future extension of the data format.

TECHNICAL FIELD

The present invention relates to recording medium formed in the shape ofa tape and encased in a cassette to a form a tape cassette, a tape driveto write or read data to or from the tape-shaped recording medium, and amethod of discriminating the type of a recording medium loaded in thetape drive.

BACKGROUND ART

As a tape drive (tape recording and/or reproducing apparatus) capable ofwriting and/or reading digital data to and/or from a magnetic tape as arecording medium, a so-called tape streaming device has been proposed.The tape streaming drive can record tens to hundreds gigabytes of datafor example. This recording capacity depends upon the length of amagnetic tape in a tape cassette used in the drive. Thus, the tapestreaming drive is widely used to back up data recorded in a medium suchas a hard disk used in a computer, etc. Also the tape streaming drive isconveniently used to store data having a large size such as image data.

As a typical example of the above-mentioned tape streaming drive, therehas been proposed a one adapted to record or reproduce data into or froman 8-mm VTR tape cassette as a recording medium by a helical scanningmethod in which a rotary head is used.

In the above tape streaming drive, it is first necessary to judgewhether or not a tape cassette loaded in the drive is a one supported bythe tape streaming drive designed and manufactured under a standard.

Even a tape cassette of a type conforming to the standard for the tapestreaming drive has to be judged to be a data storage one or a cleaningcassette.

Further, if there is available a plurality of data formats for the datastreaming drive, it is necessary for even a tape cassette meeting thestandard for the tape streaming drive to meet one of the data formatsthe tape cassette supports.

That is, the tape streaming drive has to be adapted to identify the typeof a tape cassette loaded therein.

Generally, for identification of a tape cassette type, an identificationhole is provided in the body of the tape cassette body and a detectionmechanism or the like is provided in the tape streaming drive to detectthe identification hole in the tape cassette body. In this case, at thetape streaming drive, the detection mechanism detects whether or not theidentification hole is provided in the body of the tape cassette loadedin the drive to identify the type of the tape cassette loaded in thedrive. Thus, it is possible to allow the tape streaming drive to operatecorrespondingly to the tape cassette type thus identified.

The tape streaming drive system has available kinds of data formatincreased frequently as necessary to improve the recording andreproduction reliability, recording density, etc. for example.Generally, it means that higher-order data formats will be added to theexisting data formats. Therefore, along with the increased number ofdata formats, the tape streaming drive has to support a correspondinglyincreased number of tape cassette types.

As a matter of fact, however, it is difficult because of the space, etc.to form additional holes in the tape cassette body correspondingly tothe addition of data formats. Also, with the addition of the dataformats, the structure of the detection mechanism in the tape streamingdrive will be complicated and larger in order to detect manyidentification holes formed in the tape cassette body. In this respect,it is not desirable to form additional identification holes in the tapecassette body correspondingly to the addition of the tape cassette typesfor use with the tape streaming drive.

DISCLOSURE OF THE INVENTION

Accordingly the present invention has an object to overcome theabove-mention drawbacks of the prior art by making it possible toidentify the type of tape cassette, especially, a data format of thetape cassette, without dependence upon the identification hole formed ina tape cassette body.

The above object can be attained by providing a recording mediumincluding, according to the present invention:

a magnetic tape;

a cassette encasing the magnetic tape; and

a memory provided in the cassette to store management information formanagement of data writeN to and/or read from the magnetic tape;

the magnetic tape having a data format for data written to and/or readfrom the magnetic tape and which corresponds to any of a plurality ofpredetermined data formats; and

the memory having set therein a storage area for storage of data formatidentification information indicative of the corresponding data format.

According to another aspect of the present invention, the memory may beprovided with terminals for transfer of information signals and whichface the outside of the cassette.

According to another aspect of the present invention, the memory may beprovided with a transmission and reception means for non-contacttransfer of information signal.

According to another aspect of the present invention, the magnetic tapemay have an area where an information signal is recorded, and the areabe divided in three or more partitions.

According to another aspect of the present invention, system logallocation flags included in data format identification informationrecorded in the magnetic tape may be adapted to indicate that the dataformat identification information is recorded in the magnetic tape, andthe data formation identification information be read from the magnetictape when data formation identification information cannot be read fromthe memory.

According to another aspect of the present invention, it may be judged,based on a native flag included in the data format identificationinformation read from the magnetic tape, which the area of the magnetictape where the information signal is recorded has, a format in which thearea is divided in three or more partitions or a format in which thearea is divided in two or less partitions.

Also the above object can be attained by providing a tape drive to writeand/or read information signals to and/or from a recording mediumcomprising a magnetic tape; a cassette encasing the magnetic tape; and amemory provided in the cassette to store management information formanagement of data written to or read from the magnetic tape; themagnetic tape having a data format for data written to or read from themagnetic tape and which corresponds to any of a plurality ofpredetermined data formats; and the memory having set therein a storagearea for storage of data format identification information indicative ofthe corresponding data format. In addition, the tape drive according tothe present invention includes;

tape driving means for writing and/or reading information signals toand/or from the magnetic tape in the loaded recording medium;

memory reading means capable of reading at least the data formatidentification information from the management information stored in thememory in the loaded recording medium; and

a data format identifying means for identifying, based on the dataformat identification information read by the memory reading means, adata format the loaded recording medium has.

According to another aspect of the present invention, the tape drive mayfurther include means may, for controlling the data driving means, thetape driving means write and/or read on information signal in a dataformat selected from at least two of the plurality of predetermined dataformats, and the controlling means allow the tape driving means to writeand/or read in the data format identified by the data format identifyingmeans.

According to another aspect of the present invention, the tape drive mayfurther include a hole detecting mechanism to detect a cleaning cassetteidentification hole formed in the cassette, where it may be judgedwhether or not the loaded recording medium is a cleaning cassette basedon the result of detection of the cleaning cassette identification holeby the hole detecting mechanism. When the recording medium is judged tobe a cleaning cassette, a mode of operation in which the cleaningcassette is used is done, while when the recording medium is judged notto be any cleaning cassette, the memory reading means reads the dataformat identification information from the memory and it may be judgedwhether the memory is, one provided with terminals for transfer ofinformation signal or one provided with a transmitting and receptionmeans for non-contact transfer of an information signal.

According lo another aspect of the present invention, the tape drive maybe adapted such that when the data format identification informationcannot be read from the memory, the data format identificationinformation is read from the magnetic tape; when system log allocationflags included in the data format identification information read fromthe magnetic tape show that the data format identification informationis recorded in the magnetic tape, it is judged based on a native flagincluded in the data format identification information read from themagnetic tape which format the area of the recording medium where theinformation signal is recorded has, a one in which the area is dividedin three or more partitions or a one in which the area is divided in twoor less partitions. When it is judged that the area of the magnetic tapein which the information signal is recorded has a format in which thearea is divided in three or more partitions, the memory is regarded asbeing faulty and the magnetic tape is used as a read-only one withprevention of the information signal from being written to the magnetictape, while when it is judged that the magnetic tape area in which theinformation signal is recorded has a format in which the area is dividedin two or less partitions, the recording medium is regarded as notprovided with the memory.

According to another aspect of the present invention, the tape drive mayfurther include:

a hole detecting mechanism for detecting whether or not a write protecthole indicating the prevention of writing of the information signal isformed in the cassette; and

a stripe sensor for optically detecting an identification stripe formedon the magnetic tape; so that:

when the data format identification information cannot be read from thememory and also reading of the data format identification informationfrom the magnetic tape is impossible, it is judged, based on the resultof write protect hole detection, Woks whether writing of the informationsignal is prevented or not;

when it is judged that writing of the information signal is notprevented, the magnetic tape is judged to have the format in which thearea of the magnetic tape where the information signal is recorded isdivided in two or less partitions;

when it is judged that write of the information signal is prevented, theidentification stripe is detected by the stripe sensor; when theidentification stripe is not detected, it is judged that the memory isnot provided and the area of the magnetic tape where the informationsignal is recorded has the format in which the area is divided in two orless partitions; and when the identification stripe is detected, readingof the data identification information from the magnetic tape is tried.

According to another aspect of the present invention, the tape drive maybe adapted such that when it is judged that the memory is not providedand the area of the magnetic tape where the information signal isrecorded has the format in which the area is divided in two or lesspartitions, the magnetic tape being coped with as a blank tape in whichinformation signal is not yet recorded.

Also the above object can be attained by providing a recording mediumtype identifying method for identification of a data format of arecording medium to and/or from which an information signal is going tobe written and/or from and which comprises a magnetic tape; a cassetteencasing the magnetic tape; and a memory provided in the cassette tostore management information for management of data written to or readfrom the magnetic tape; the magnetic tape having a data format for datawritten to or read from the magnetic tape and which corresponds to anyof a plurality of predetermined data formats; and the memory having settherein a storage area for storage of data format identificationinformation indicative of the corresponding data format; the methodincluding, according to the present invention, steps of:

reading at least the data format identification information from themanagement information stored in the memory in the recording mediumused; and

identifying, based on the data format identification information read bythe memory reading means, a data format the loaded recording medium has.

According to another aspect of the present invention, the method mayfurther include a step of detecting whether or not a cleaning cassetteidentification hole is formed in the cassette of the recording medium;when it is judged based on the result of detection of the cleaningcassette identification hole whether the recording medium used is acleaning cassette or not; when it is judged that the recording mediumused is not any cleaning cassette, the data format identificationinformation is read from the memory and it being judged whether whichthe memory is, a one provided with terminals for transfer of aninformation signal or a one provided with a transmitting and receptionmeans for non-contact transfer of the information signal.

According to another aspect of the present invention, the method may beadapted such that when the data format identification information cannotbe read from the memory, the data format identification information isread from the magnetic tape; when system log allocation flags includedin the data format identification information read from the magnetictape show that the data format identification information is recorded inthe magnetic tape, it is judged based on a native flag included in thedata format identification information read from the magnetic tape whichformat the area of the recording medium where information is recordedhas, a one in which the area is divided in three or more partitions or aone in which the area is divided in two or less partitions;

when it is judged that the area of the magnetic tape in which theinformation signal is recorded has a format in which the area is dividedin three or more partitions, the memory is regarded as is faulty and themagnetic tape being used as a read-only one with prevention of theinformation signal from being written to the magnetic tape; and

when it is judged that the magnetic tape area in which the informationsignal is recorded has a format in which the area is divided in two orless partitions, the recording medium is regarded as not provided withthe memory.

According to another aspect of the present invention, the method may beadapted such that when the data format identification information cannotbe read from the memory and also reading of the data formatidentification information from the magnetic tape is impossible, it isjudged, based on the result of write protect hole detection, whetherwriting of the information signal is prevented or not;

when it is judged that writing of the information signal is notprevented, the magnetic tape is judged to have the format in which thearea of the magnetic tape where the information signal is recorded isdivided in two or less partitions; and

when it is judged that write of the information signal is prevented, theidentification stripe is detected by the stripe sensor; when theidentification stripe is not detected, it is judged that the memory isnot provided and the area of the magnetic tape where the informationsignal is recorded has the format in which the area is divided in two orless partitions; and when the identification stripe is detected, readingof the data identification information from the magnetic tape is tried.

According to another aspect of the present invention, the method may beadapted such that when it is judged that the memory is not provided andthe area of the magnetic tape where the information signal is recordedhas the format in which the area is divided in two or less partitions,the magnetic tape is judged to be a blank tape in which the informationsignal is not yet recorded.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a tape streaming drive which is the tapedrive according to the present invention.

FIG. 2A schematically shows the internal structure of a tape cassette(having a remote type MIC) which is the recording medium according tothe present invention.

FIG. 2B schematically shows the internal structure of a tape cassette(having a contact type MIC) which is also the recording medium accordingto the present invention.

FIG. 3 is a perspective view of the tape cassette.

FIG. 4A shows a data structure recorded in the magnetic tape in the tapecassette.

FIG. 4B shows the inside of a partition in the data structure recordedin the magnetic tape in the tape cassette.

FIG. 4C shows the inside of a group in the data structure recorded inthe magnetic tape in the tape cassette.

FIG. 4D shows the inside of a frame in the data structure recorded inthe magnetic tape in the tape cassette.

FIG. 5A schematically shows the data structure of one block in a datastructure recorded in the magnetic tape.

FIG. 5B schematically shows the data structure of one track in a datastructure recorded in the magnetic tape.

FIG. 5C schematically shows the data structure of one frame in a datastructure recorded in the magnetic tape.

FIG. 6A shows the construction of an area on the magnetic tape.

FIG. 6B shows the construction of a data area on the magnetic tape.

FIG. 6C shows the construction of a system area on the magnetic tape.

FIG. 7A shows a tape layout on the magnetic tape when in the normal mode(one-partition mode).

FIG. 7B shows a tape layout on the magnetic tape when in the normal mode(two-partition mode).

FIG. 7C shows a tape layout in the magnetic tape when in themulti-partition mode.

FIG. 8 shows the data structure in the MIC of the tape cassette.

FIG. 9 shows the manufacture part in the MIC of the tape cassette.

FIG. 10 shows the definition of the MIC type in the tape cassette.

FIG. 11 shows the drive initialize part in the MIC of the tape cassette.

FIG. 12 shows the volume attribute flag in the MIC of the tape cassette.

FIG. 13 shows the volume tag in the MIC of the tape cassette.

FIG. 14 shows the volume information in the MIC of the tape cassette.

FIG. 15 shows the volume information on tape in the MIC of the tapecassette.

FIG. 16 shows the system log allocation flag showing that the system logis in the MIC of the tape cassette.

FIG. 17 shows the definition of AIT native flag in the tape cassette.

FIG. 18A shows the cell structure of the MIC of the tape cassette.

FIG. 18B shows the link information in the MIC of the tape cassette.

FIG. 19 shows the partition information cell in the MIC of the tapecassette.

FIG. 20 shows the partition information in the MIC of the tape cassette.

FIG. 21 shows the super-high speed search map cell in the tape cassette.

FIG. 22A is a plan view of an AIT-1 cassette.

FIG. 22B is a perspective view of the AIT-1 cassette.

FIG. 23A is a plan view of an AIT-2 cassette.

FIG. 23B is a perspective view of the AIT-2 cassette.

FIG. 24A is a sectional view showing the operations effected when thewrite protect hole in the AIT-2 cassette is opened.

FIG. 24B is a sectional view showing the operations effected when thewrite protection hole in the AIT-2 cassette is closed.

FIG. 25 is a side elevation of the internal mechanism of the tapestreaming drive when a tape cassette not conforming to the specificationof the tape streaming drive is loaded in the tape streaming drive.

FIG. 26 is a side elevation of the mechanism of the tape streaming drivewhen a tape cassette conforming to the specification of the tapestreaming drive is loaded in the tape streaming drive.

FIG. 27A shows the construction of an identification stripe formed onthe leader tape in the tape cassette.

FIG. 27B shows the definition of the identification stripe formed on theleader tape in the tape cassette.

FIG. 28 is a block diagram of an IF/ECC controller supporting the dataformat.

FIG. 29 is a flow chart (routine for checking the MIC and magnetic tape)of operations effected to identify the data format and tape format of atape cassette loaded in the tape streaming drive.

FIG. 30 is a flow chart (routine to be executed when the MIC andmagnetic tape are defective) of operations effected to identify the dataformat and tape format of a tape cassette loaded in the tape streamingdrive.

FIG. 31 is a flow chart (routine to be executed when the MIC isdefective while the magnetic tape is defective) of operations effectedto identify the data format and tape format of a tape cassette loaded inthe tape streaming drive.

FIG. 32 is a flow chart (routine to be executed when the MIC isdefective) of operations effected to identify the data format and tapeformat of a tape cassette loaded in the tape streaming drive.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will further be described below concerning theembodiments of the present invention with reference to the accompanyingdrawings.

The embodiments going to be described herein are applications of thepresent invention to a tape cassette provided with a memory and a datastorage system in which the tape cassette with the memory can be used,respectively. The tape cassette provided with the memory and the datastorage system, according to the present invention, correspond to thetape cassette provided with a nonvolatile memory and tape drive forminga data storage system capable of writing and/or reading digital data toand/or from the tape cassette with the memory, both having already beenproposed by the Application of the present invention. The nonvolatilememory provided in the tape cassette will be referred to as “MIC (memoryin cassette)” hereinafter.

The present invention will be described herein in the following order:

1. Construction of tape cassette

2. Construction of tape streaming drive

3. Data structure on magnetic tape

4. Data structure in MIC

5. Structure of tape cassette, which supports data format

5-1. Identification holes in tape cassette body

5-2. Magnetic tape identification stripe

6. Construction of tape streaming drive, which supports data format

7. Operations to identify data format

1. Construction of tape cassette

First, the tape cassette being a recording medium used in the tapestreaming drive or library device according to the present inventionwill be described with reference to FIGS. 2A, 2B and 3.

FIG. 2A shows the concept of the internal structure of the tape cassetteprovided with an MIC (remote type MIC) as a memory chip. As shown, acassette 1 has a pair of reels 2A and 2B provided therein. A magnetictape 3 of 8 mm in width is wound on, and extends between, the reels 2Aand 2B.

As shown, the cassette 1 has provided therein a remote type MIC 4Aincorporating a nonvolatile memory and a control circuit for the memory.The remote type MIC 4A can make mutual communications of data signals,etc. with a remote memory interface 30 in the tape streaming drive orlibrary device as will further be described later. The remote type MIC4A is provided with an antenna 4 a for the data transmission.

The remote type MIC 4A stores manufacture information and serial numberinformation on each tape cassette, a thickness, length and material ofthe magnetic tape, history of use of recorded data in each partition,user information, etc., as will further be described later.

The above-mentioned various kinds of information stored in the remotetype MIC 4A will also be referred collectively to as “managementinformation” hereinafter since they are used mainly to manage the datawritten or read to or from the magnetic tape 3 in various manners.

The tape cassette has provided in the body thereof the nonvolatilememory in which management information is stored and the tape streamingdrive for that tape cassette has the interface for data written and readto or from the nonvolatile memory. Thus, by writing or reading to orfrom the nonvolatile memory the management information on the datawritten to or read from a magnetic tape in the tape cassette, data canefficiently be written to or read from the magnetic tape 3.

For example, the tape cassette can be loaded into or unloaded from thetape streaming drive even with the magnetic tape being stopped in themid way. For loading or unloading of the tape cassette, it is notnecessary to rewind the magnetic tape to its leading end for example.Also, data can be edited by rewriting the management information in thenonvolatile memory. Moreover, more partitions can be set on the magnetictape for more appropriate management of the data write and/or readoperations.

FIG. 2B shows a tape cassette incorporating a contact type MIC(nonvolatile memory) 4B.

In this embodiment, five terminals 5A, 5B, 5C, 5D and 5E are led outfrom the module of the contact type MIC 4B. These five terminals areused as a power terminal, data input terminal, clock input terminal,grounding terminal and an auxiliary terminal, respectively.

The contact type MIC 4B stores similar information to that stored in theremote type MIC 4A as the remote memory chip.

FIG. 3 is an external view of the tape cassette shown in FIG. 2A or 2B.The entire cassette body consists of an upper case 6 a, lower case 6 band a guard panel 8. This construction is basically similar to that of atape cassette which is used in a common so-called “8-mm VTR”.

A terminal block 7 is provided near a label surface 9 at the lateralside of the tape cassette.

Further, on the tape cassette incorporating the contact type MIC 4Bshown in FIG. 2B, terminal pins 7A, 7B, 7C, 7D and 7E are provided atpositions corresponding to those of the electrodes, respectively, andconnected to the terminals 5A, 5B, 5C, 5D and 5E, respectively, shown inFIG. 2B) That is, with the terminal pins 7A, 7B, 7C, 7D and 7E put inphysical connection to the tape streaming drive 10 which will further bedescribed later, the tape cassette having the contact type MIC 4 (4B)can make mutual communications of data signals, etc. with the tapestreaming drive 10 via the terminal pins 7A, 7B, 7C, 7D and 7E.

On the other hand, the terminal pins are of course unnecessary for thetape cassette having the remote (non-contact) type memory chip providedtherein as MIC as shown in FIG. 2A. However, this tape cassette has theappearance as shown in FIG. 3. Namely, to assure the same shape as thatof the tape cassette shown in FIG. 2B, the terminal pins 7A to 7E areprovided also on the tape cassette in FIG. 2A but they are dummy ones sothat this tape cassette can also be played in the tape streaming drive.

Note that in the following description, when the remote type MIC 4A andcontact type MIC 4B are collectively referred to herein or where it isnot necessary to make any discrimination between the remote type MIC 4Aand contact type MIC 4B in description of them, they will be referred tosimply as MIC4.

2. Construction of tape streaming drive

Next, the tape streaming drive being the embodiment of the presentinvention will be described herein with reference to FIG. 1. The tapestreaming drive is generally indicated with a reference 10 and adaptedto make write or read information signal to or from the magnetic tape 3in the aforementioned tape cassette by the helical scan method.

As shown in FIG. 1, there is provided a rotary drum 11 having two writeheads 12A and 12B and three read heads 13A, 13B and 13C for example.

The write heads 12A and 12B have their respective gaps different inazimuth angle from each other which are laid in close vicinity of eachother. The read heads 13A and 13B are different in azimuth angle fromeach other and disposed at 90 deg. for example in relation to eachother.

The rotary drum 11 is rotatable by a drum motor 14A, and has woundedthereon the magnetic tape 3 led out of the tape cassette.

The magnetic tape 3 is moved by a capstan motor 14B and pinch rollers(not shown). As mentioned above, the magnetic tape 3 is wound on thereels 2A and 2B. The reels 2A and 2B are rotated by reel motors 14C and14D, respectively, in the forward and backward directions, respectively.

The drum motor 14A, capstan motor 14B, and the reel motors 14C and 14Dare supplied each with a power from a mechanical driver 17. Themechanical driver 17 drives each of the motors under the control of aservo controller 16. The servo controller 16 controls the speed of eachmotor to move the magnetic tape for ordinary recording and reproduction,high speed reproduction, fast forwarding and for rewinding.

There is provided an EEP-ROM 18 having stored therein constants theservo controller 16 uses for servo control of each of the motors.

The servo controller 16 is bidirectionally connected to a systemcontroller 15 via an interface controller/ECC formatter 22 (will bereferred to as “IF/ECC controller” hereinafter). The system controller15 controls the entire system of the tape streaming drive.

There is also provided a hole detecting mechanism 26 to detect each ofidentification holes formed in the tape cassette loaded in the tapestreaming drive. The hole detecting mechanism 26 is composed of pinscorresponding to the identification holes, photosensors, etc. forexample.

The tape cassette has formed therein various identification holes whichare to be closed and opened depending upon the type of a tape containedin the tape cassette and whether or not the write protect function isapplied, in compliance with a predetermined standard. The hole detectingmechanism 26 detects such holes.

Detection information from the hole detecting mechanism 26 is suppliedto the system controller 15 which can know the type of the tape in thetape cassette and whether or not the write protection function isapplied.

The identification holes formed in the tape cassette according to thepresent invention will further be described later.

Also there is provided a stripe sensor 26 a to detect an identificationstripe formed on the leader tape in the tape cassette based on apredetermined data format applied to the tape cassette. Theidentification stripe is detected by the stripe sensor 26 a will furtherbe described later.

The tape streaming drive 10 uses an SCSI interface 20 for data input andoutput. For data recording for example, data are sequentially suppliedin fixed-length records from a host computer 40 to a compander(compressor/expander) 21 via the SCSI interface 20. For the tapestreaming drive of this type, there is available a mode in which dataare transmitted in data aggregates from the host computer 40.

The compander 21 compresses the supplied data by a predetermined methodif necessary. In a compression method using LZ code for example, adedicated code is assigned to a character string having been processedin the past, and cumulatively stored in the form of a dictionary. Asubsequently entered character string is compared with the content ofthe dictionary. When the comparison result shows that the inputcharacter string coincides with the code in the dictionary, the inputcharacter string is replaced with the code in the dictionary. If thecomparison result does not show that the input character stringcoincides with the code in the dictionary, a new code is assigned to theinput character string and registered into the dictionary. Data in inputcharacter strings is thus registered and the character string data isreplaced with the code in the dictionary, thereby compressing the data.

The output of the compander 21 is supplied to the IF/ECC controller 22,and stored once into a buffer memory 23 under the control of the EF/ECCcontroller 22. The data stored in the buffer memory 23 are finallytreated in groups each of which has a fixed length equal to 40 tracks onthe magnetic tape 40. The data is ECC-formatted.

In the ECC formatting, an error correction code is appended to ato-be-recorded data and the data is modulated for magnetic recording,and then the modulated data into supplied to an RF processor 19.

Note that in the embodiment of the present invention, there is availablea plurality of data formats for data which is to be written to or readfrom the magnetic tape. In this embodiment, the data formats willcollectively be referred as “AIT (advance intelligent tape)”.

The tape streaming drive 10 according to the present invention isadapted to support two AIT formats, one being an AIT-1 and the otherbeing AIT-2 which is an extended version of AIT-1.

Note also that the tape cassette according to the present invention isbasically adapted to support AIT-1 or AIT-2. Actually, the tapecassettes adapted to support these AIT formats according to the presentinvention basically include ones provided with MIC 4, but some of thetape cassettes are not provided with MIC 4.

The RF processor 19 amplifies, equalizes and processes otherwise thesupplied to-be-recorded data to generate a recording signal for supplyto the write heads 12A and 12B. Thus, the write heads 12A and 12B writethe data to the magnetic tape 3.

The data read will be outlined herebelow. Recorded data is read from themagnetic tape 3 by the read heads 13A and 13B as RF read signal. Outputsfrom the read heads 13A and 13B are equalized, processed to generate aclock, binary-coded, and decoded (Viterbi-decoded, for example) in theRF processor 19.

The signal thus read is supplied to the IF/ECC controller 22 where it iserror-corrected first of all. The error-corrected signal isprovisionally stored in the buffer memory 23. It will be read at apredetermined time and supplied to the compander 21.

The read signal will be expanded by the compander 21 if it is judged bythe system controller 15 to be data having been compressed by thecompander 21 when it was written. If it is judged not to be compressed,it will be passed and provided as an output without being expanded.

The data output from the compander 21 is provided as a read data to thehost computer 25 (40) via the SCSI interface 20.

Also in FIG. 1, there are shown both the remote type MIC 4A and contacttype MIC 4B as MIC 4 each provided in the tape cassette. Actually,however, a tape cassette provided with MIC has either the remote typeMIC 4A or contact type MIC 4B is provided therein.

When a tape cassette provided with the remote type MIC 4A is insertedinto the tape streaming drive, data can be transferred between theremote type MIC 4A and system controller 15 via a remote memoryinterface 30 in a contactless manner.

The remote memory interface 30 includes a data interface 31, RFinterface 32 and an antenna 33.

The remote memory interface 30 functions as will be outlined below:

The data interface 31 is a means via which data is transferred betweenthe remote type MIC 4A and system controller 15 as mentioned above. Datais transferred to the remote type MIC 4A by transmitting a command fromthe tape streaming drive and returning an acknowledge from the remotetype MIC 4A upon reception of the command. A command issued to theremote type MIC 4A from the system controller 15 is received by the datainterface 31, and supplied to the RF interface 32. The data interface 31supplies a carrier frequency (13 MHZ) to the RF interface 32.

The RF interface 32 will modulate the amplitude of a command signal (100kHz) and superpose it on the carrier frequency, and amplify themodulated signal. The amplified modulated signal is provided to theantenna 33. Thus, the command data is wirelessly transmitted from theantenna 33 to the antenna 4 a in the tape cassette 1. The tape cassetteis powered by receiving the command data by the antenna 4 a and thesystem controller 15 provided in the remote type MIC 4A will operate ina predetermined manner according to the command. For example, datatransmitted along with the write command is written into the EEP-ROM 18.

When a command is issued from the remote memory interface 30 as in theabove, the remote type MIC 4A will issue a corresponding acknowledge andtransmit it from the antenna 4 a.

When the acknowledge is received by the antenna 33, it will be rectifiedin the RF interface 32 and then demodulated as a binary-coded data bypassing it through a comparator, for example. The binary data issupplied from the data interface 31 to the system controller 15. When aread command is issued from the system controller 15 to the remote typeMIC 4A for example, the latter will send data from its internal memoryelement along with a code as an acknowledge corresponding to the readcommand. Then, the acknowledge code and read data are received andmodulated by the remote memory interface 30, and supplied to the systemcontroller 15.

As in the above, the tape streaming drive 10 is able to access theremote memory chip (MIC) 4 in the tape cassette 1 via the remote memoryinterface 30.

Note that for the non-contact data exchange, data is superposed on a13-MHZ carrier frequency by 100-kHz amplitude modulation while itsinitial data is packeted.

That is, data as command and acknowledge are packeted by appendingthereto header, parity and other necessary information, and the packetis code-converted before being modulated, thereby transmitting andreceiving the data as a stable RF signal.

Note that the technique to implement the aforementioned non-contactinterface has been proposed by the Applicant of the present inventionand patented as the Japanese Patent No. 2550931.

On the contrary, when the tape cassette provided with the contact typeMIC 4B is inserted into the tape streaming drive 10, the terminals 7A to7E shown in FIG. 3 are put into contact with a connector 27 of the tapestreaming drive 10 to provide an electrical connection between them fordata transfer between the tape cassette side and system controller 15.Thus, the system controller 15 can read and update managementinformation recorded in the contact type MIC 4B.

Information is transferred between the tape streaming drive 10 and hostcomputer 40 via the SCSI interface 20 as in the above. The host computer40 will use SCSI commands to make a variety of communications with thesystem computer 15.

Therefore, the host computer 40 can issue SCSI commands to have thesystem controller 15 effect data written to or read from MIC 4.

Further there are provided an S-RAM 24 and flash ROM 25 in which thereare stored data used by the system controller 15 to do a variety ofoperations.

For example, the flash ROM 25 stores constants used in controlling. TheS-RAM 24 is used as a work memory and a memory to store and process dataread from MIC 4, data for written into MIC 4, mode data set for eachtape cassette and various flag data.

The S-RAM 24 and flash ROM 25 may be adapted as internal memories in amicro computer forming the system controller 15, and a partial area ofthe buffer memory 23 may be adapted to function as a work memory.

The above mode set for each tape cassette is a one set depending upon aformat in which the magnetic tape in the tape cassette has beeninitialized. It is either a normal mode or a multi-partition mode. Inother words, these modes refer to tape formats in which the magnetictape is initialized.

The normal mode is used to format the tape cassette in one partition ortwo partitions. On the other hand, the multi-partition mode is used toformat the tape cassette in three or more partitions.

Also when the tape cassette is formatted in the multi-partition mode, itcan be loaded or unloaded even while data is yet being written to orread from any of the partitions (namely, even when the magnetic tape hasnot been returned to the leading end or trailing end).

The above mode setting or tape formatting is done by the tape streamingdrive 10 for a tape cassette having not yet been set to any mode or atape cassette which should desirably be initialize for the purpose ofmode change. When a tape cassette which is not set in any of the abovemodes is loaded in the tape streaming drive 10, it will be judged towhich tape format the tape cassette has been set, and the systemcontroller 15 will set the tape streaming drive for operation in themode to which the tape cassette has been set.

When the tape cassette loaded in the tape streaming drive is a oneprovided with the above-mentioned MIC, either the multi-partition ornormal mode can freely be selected. If the tape cassette is a one withno MIC, only the normal mode can be selected.

3. Data structure on magnetic tape

The data format on the magnetic tape 3 in the tape cassette to or fromwhich data is written or read by the aforementioned tape streaming drive10 will be outlined below:

FIGS. 4A, 4B, 4C and 4D show the structure of data recorded on themagnetic tape 3. FIG. 4A schematically shows one magnetic tape 3.According to the present invention, the single magnetic tape 3 can bedivided in units of a partition for practical use as shown. In the tapestreaming drive 10 according to the present invention, a single magnetictape can be divided into a maximum of 256 partitions for the purpose ofdata write or read management. As shown in FIGS. 4A, 4B, 4C and 4D, thepartitions are assigned numbers #0, #1, #2, #3, . . . with which thepartition are managed.

Therefore, according to the present invention, it is possible to writeor read data independently to or from each of the partitions on themagnetic tape. As shown in FIG. 4B, each of the partitions can bedivided into fixed-length units called “group” as shown in FIG. 4C.Recording is made to each group in each of the partitions on themagnetic tape 3.

In this case, one group consists of 20 frames, and one frame consists oftwo tracks as shown in FIG. 4D. Namely, the two tracks in one frame areadjacent to each other and have a positive azimuth and negative azimuth,respectively. Therefore, one group is formed from 40 tracks.

The data structure on one track shown in FIG. 4D is shown in furtherdetail in FIGS. 5A and 5B. FIG. 5A shows the data structure in one blockformed from a one-byte sync data area A1, 6-byte ID area A2 for used insearching, 2-byte error correction parity area A3 for ID data, and a64-byte data area A4.

As shown in FIG. 5B, data. in one track consists of a total of 471blocks. Also as shown in FIG. 5B, one track has margin areas A11 and A19for 4 blocks at opposite ends thereof. An ATF area A12 is defined afterthe margin area A11 and another ATF area A18 is defined before themargin area A19. Further, the ATF area A12 is followed by a parity errorarea A13 and a parity error area A17 is defined before the ATF area A18.Each of these parity error areas A13 and A17 includes 32 blocks.

An ATF area A15 is provided in the middle of one track. Each of theseATF areas A12, A15 and A18 includes 5 blocks. Further, a 192-block dataarea A14 is provided between the parity area A13 and ATF area A15, andanother 192-block data area A16 is provided between the ATF area A15 andparity area A17. Therefore, the data areas A14 and A16 in one trackshare 384 blocks (192×2) of the total of 471 blocks.

Thus, the tracks are physically recorded on the magnetic tape 3 as shownin FIG. 5C, and 40 tracks (=20 frames) will be taken as one group as inthe above.

In the magnetic tape 3 having been described in the above with referenceto FIGS. 4A, 4B, 4C and 4D and FIGS. 5A, 5B and 5C, data will berecorded in an area structure as will be described below with referenceto FIGS. 6A, 6B and 6C.

Note that in an example which will be described herein, the magnetictape is set to have N partitions #0, . . . , #N−1.

As shown in FIG. 6A, the magnetic tape physically consists of a leadertape at the beginning (top) thereof, which is followed by a device areafor allowing to load or unload the tape cassette. The top of this devicearea is taken as a physical beginning of tape (PBOT).

The device area is followed by a reference area for the partition #0 andsystem area in which history of use of the magnetic tape is stored(these reference and system areas will collectively be referred to as“system area” hereinafter). The device area is further followed by adata area. The top of the system area is taken as a logical beginning oftape (LBOT).

As shown enlarged in scale in FIG. 6C, the system area includes areference area, position tolerance band No. 1, system preamble, systemlog, system postamble, position tolerance band No. 2, and a vender grouppreamble.

According to this embodiment, it is defined that there should berecorded in the system log area information having the nearly samecontent as management information which is stored in MIC 4, as will bedescribed later.

As shown enlarged in scale in FIG. 6B, the data area following thesystem area includes a vender group indicative of information on avender who first generates and supplies data, and a plurality ofsuccessive groups indicated with references 1 to (n) and which havealready been shown in FIG. 4C. Finally an amble group is providedfollowing the last group (n).

As shown in FIG. 6A, the data area is further followed by an end of data(EOD) area indicative of the end of data area in the partition.

When only one partition is formed on the magnetic tape, the end of theEOD of the partition #0 will be taken as a logical end of tape (LEOT) ofthe magnetic tape. In this example, however, since the N partitions areformed on the magnetic tape, the EOD of the partition #0 is followed byan optional device area.

The device area ranging from the above-mentioned top position PBOT isintended for tape cassette loading and/or unloading corresponding to thepartition #0, and the last optional device area in the partition #0 isintended for tape cassette loading and/or unloading corresponding-to thepartition #1.

The partition #1 consists of areas as in the partition #0, and it endsin an optional device area intended for tape cassette loading or loadingcorresponding to a next partition #2.

The subsequent partitions down to #(N−1) have a similar structure to theabove.

Note that the last partition #(N−1) has no optional device area becausethe latter is not required but its EOD ends in a logical end of tape(LEOT).

PEOT stands for physical end of tape. Namely, it indicates the physicalend of the magnetic tape or physical end of the partition.

As having also been described, the tape is formatted in either thenormal or multi-partition mode in this embodiment. The tape layout willbe described herein concerning each of the normal mode (DDS mode) andmulti-partition mode with reference to FIGS. 7A, 7B and 7C.

FIG. 7A shows an example that the magnetic tape is formatted in thenormal mode to have one partition.

In this case, only the partition #0 is formed to have a structuresimilar to that of the last partition #(N−1) shown in FIGS. 6A, 6B and6C for example. That is, the partition #0 in this example has nooptional device area at the trailing end thereof.

FIG. 7B shows an example that the magnetic tape is formatted in thenormal mode to have two partitions, namely, partitions #1 and #0, asshown. In case two partitions are provided in the normal mode, however,the partition #1 is disposed at the leading end of the magnetictape.while the partition #0 is provided after the partition #1.

The tape formatting in the normal mode shown in FIGS. 7A and 7B can bedone with any of tape cassettes with and without MIC 4, respectively.

FIG. 7C shows an example that the magnetic tape is formatted in themulti-partition mode to have a plurality of partitions #0 to #(N−1).

It is required according to the standard that when the multi-partitionmode is applied for tape formatting, the magnetic tape should beformatted so that the partition #0 is at the topmost position of themagnetic tape, followed by the partition #1, . . . , partition #(N−2)and the partition #(N−1). Each of the partitions will be provided withan optional device area at the trailing end thereof in addition to theareas having been described with reference to FIGS. 5A, 5B and 5C. Thatis, the tape layout is the same as shown in FIG. 6A.

As having been described in the foregoing, the device area near thebeginning end of the tape is for tape loading or unloading. The optionaldevice area is provided to allow the tape loading or unloading at eachpartition (namely, when the tape is not at the leading or trailing end).

The tape layout in the multi-partition mode as shown in FIG. 7C can berealized only with a tape cassette provided with MIC 4.

The AIT-1 and AIT-2 are available as the data formats for the embodimentof the present invention as having previously been described. Both thedata formats AIT-1 and AIT-2 are compatible with both tapes formatted(initialized) in the normal and multi-partition modes.

Note that the normal mode will also be referred herein to as “DDS mode”for the convenience of description.

4. Data structure in MIC

Next, the structure of data stored in MIC 4 provided in the tapecassette 1 will be described herein:

FIG. 8 schematically shows a structure example of data stored in MIC 4.In the storage area of MIC 4, there are set fields FL1 to FL4 as shownin FIG. 8.

A variety of information on the manufacture of the tape cassette,information on the tape initialization and information in each partitionare written into these fields FL1 to FL4.

The field FL1 is a manufacture part for storing manufacture informationincluding a variety of information on the manufacture of the tapecassette.

The field FL2 is a drive initialize part for storing memory managementinformation including mainly information on the tape initialization.

The field FL3 is a volume tag part for storing basic managementinformation for the entire tape cassette.

The field FL4 is a memory-free pool area in which management informationcan additionally be stored. The memory-free pool stores a variety ofinformation correspondingly to the progress of data write or readoperation or as necessary. Note that one unit of data group stored inthe memory-free pool will be referred to as “cell” hereinafter.

Partition information cells #0, #1, . . . being engagement informationcorresponding to the partitions, respectively, formed on the magnetictape 3 are sequentially written starting at the top of the memory-freepool. Namely, there are formed as many partition information cells asthe partitions formed on the magnetic tape 3.

Also, a super-high speed search map cell as map information forhigh-speed search is written starting at the trailing end of thememory-free pool.

Next, a user volume note cell and user partition note cell are writtenin this order toward the top of the storage area of the MIC 4 startingat the end of the super-high speed search map cell. The user volume notecell is information such as a comment entered by the user concerning theentire tape cassette, and the user partition note cell is informationsuch as a comment entered by the user concerning each partition.Therefore, the user volume note cell and user partition note cell arestored when the user gives a write instruction. A11 the information willnot be described.

The intermediate area in which the above information is not stored isleft as a memory-free pool into which data is to be written later.

The manufacture information in the field FL1 has a structure as shown inFIG. 9 for example. The size of each data (in bytes) is shown at theleft.

The manufacture information includes first a “manufacture part checksum”of one byte. The “manufacture part checksum” is a checksum ofmanufacture information. The manufacture part checksum is given to eachmagnetic tape at the time of tape cassette manufacture.

The actual data in the manufacture part includes data ranging from a“MIC type” to “write protected data byte count”. Note that in the fieldFL1, “reserved” indicates an undefined area used as an auxiliary areafor future data storage. This is also true for the followingdescription.

The “MIC type” indicates the type of a MIC actually provided in the tapecassette and a data format the tape cassette should support. Thedefinition of the MIC type will further be described later.

The manufacture information in the field FL1 further includes a “MICmanufacture data” indicating the date (and hours) on which the MIC wasmanufactured.

The manufacture information includes also a “MIC manufacture line name”indicating the name of the manufacture line along which the MIC wasmanufactured.

The manufacture information includes a “MIC manufacture plant name”indicating the name of the plant where the MIC was manufactured.

Also the manufacturer information includes a “MIC manufacturer name”indicating the name of the manufacturer who manufactured the MIC.

The manufacture information further includes a “MIC name” indicating thename of the vender from whom the MIC was supplied or bought.

Further the manufacture information includes a “cassette manufacturedata”, “cassette manufacture line name”, “cassette manufacture plantname”, “cassette manufacture name” and “cassette name”, similar to theaforementioned information on the MIC.

The manufacture information also includes an “OEM customer name”indicating the name of the original equipment manufacturer (OEM).

The manufacture information further includes “physical tapecharacteristic ID” such as tape material, thickness and length.

Also the manufacture information includes a “maximum clock frequency”indicating the maximum clock frequency the MIC can support.

The manufacture information includes a “maximum write cycle” indicatinghow many bytes of data can be transferred by one communication with thetape streaming drive 10. This information depends upon the physicalcharacteristic of a nonvolatile memory used as the MIC.

The manufacture information also includes a “MIC capacity” indicatingthe storage capacity of the MIC.

The manufacture information includes a “write protect start address”used to prevent a predetermined part of the MIC from being written, andindicating an address at which the write-protected area starts.

The manufacture information also includes a “write protect byte count”indicating a number of bytes of the write-protected area. That is, anarea occupied by the number of bytes specified in the “write protectbyte count” area starting at an address specified in the above “writeprotect start address” will be set as a write-protected area.

FIG. 10 shows the definition of the “MIC type” area shown as a fieldFL11 in FIG. 9.

The “MIC type” area is of one byte as shown in FIG. 9 as well. In thisarea, the seventh to fourth bits indicate a data format the tapecassette in consideration can support, and third to 0-th bits indicate atype of the MIC provided in the tape cassette.

When the seventh to fourth bits take a value “0000”, the tape cassettecan support the AIT-1 format. When these bits take a value “0001”, thetape cassette can support the AIT-2 format. When the bits take a value“0010”, the tape cassette can support the AIT-3 format. When the bitstake a value “0011”, the tape cassette can support the AIT-4 format. Theareas showing values “0100” to “1111” of these bits are currentlyreserved.

Therefore, even if a data format AIT-5 or more for example isstandardized in future, areas can be reserved for new data formats, tothereby sufficiently support future data formats.

When the four bits, namely, the third to 0-th bits take a value “0001”,the contact type MIC 4B with five pin terminals shown in FIG. 2B isprovided in the tape cassette. A value “0101” these bits take means thatthe MIC provided in the tape cassette is the remote type MIC 4A shown inFIG. 2A. At present, only these two values of the third to 0-th bits aredefined. The remaining values “0000”, “0010” to “0100”, “0110” and“1111” are not yet defined.

As having previously been described, only the data formats AIT-1 andAIT-2 are standardized at present. Since the remote type MIC 4A can beprovided in a tape cassette which can support the data format AIT-2 inpractice, the values indicating the MIC type can only be combinations invalue, “xxxx” and “xxxx”, of the seventh to fourth bits and third to0-th bits at present, that is, “0000” and “0001” for AIT-1 and contacttype MIC, “0001” and “0001” for AT-2 and remote type MIC, and “0001” and“0101” for AIT-2 and contact type MIC.

The memory management information in the field FL2 in FIG. 8 has astructure which will be described below with reference to FIG. 11. Thesize of each data (in bytes) is shown at the right.

The memory management information includes first a “drive initializepart checksum” where a checksum of a memory management information in adrive initialize part is store

The “drive initialize part checksum” is followed by real data including“MIC logical format type” to “free pool bottom address”.

An ID number for the MIC logical type is stored as the “MIC logicalformat type”. The MIC formats include, in addition to the basic MICformat, a firmware update MIC format, reference tape MIC format,cleaning tape cassette MIC format, for example. An ID numbercorresponding to the MIC format of the tape cassette is stated in thisarea.

Further to the “MIC logical format type”, an “absolute volume mappointer” is included in the memory management information. A pointerindicative of the top address of the “absolute volume map informationcell” in FIG. 8 is disposed in this area.

The memory management information further includes a “user volume notecell pointer” which indicates a storage area of the tape cassette to orfrom which data can freely be written or read by the user via the SCSIinterface, that is, a start address of the “user volume note cell” inFIG. 8.

Further to the above, there is provided a “user partition note cellpointer” indicating a storage area of a partition to or from which datacan freely be written or read by the user via the SCSI interface, thatis, a start address of the “user partition note cell” in FIG. 8. Notethat in case there is a plurality of user partition note cells, the userpartition note cell pointer indicates a start address of the top one ofthe plurality of user partition note cells.

The memory management information includes also a “partition informationcell pointer” which indicates a start address of the “partitioninformation cell #0” in FIG. 8.

Partition information to be written into the memory free pool will beformed in an number as many as the partitions formed on the magnetictape 3. All the partitions #0 to #N are concatenated to each other bythe pointer owing to a linkage structure. That is, the partitioninformation cell pointer provides a route indicating the address of thepartition #0, and each of pointers of subsequent partition informationcells are disposed within a partition information cell just before eachof the partition information cells.

As in the above, data positions in the field FL4 are managed with thepointers (absolute volume map pointer, user volume note cell pointer,user partition note cell pointer and partition information cellpointer).

The memory management information includes also a “volume attributeflags” of one byte for providing a logical write protect tab to preventwrite to the MIC 4. The MIC head flag allows and/or prevents data writeto the manufacture part or to other part than the manufacture part.

Further to the “volume attribute flags”, a “free pool top address” and“free poll bottom address” areas are included in the memory managementinformation area. They indicate a concurrent start address and endaddress of the memory free pool in the field FL2. Since the area of thememory free pool varies depending upon the write or erase of thepartition information, user partition note, etc., the free pool topaddress and free pool bottom address are correspondingly updated.

The volume attribute flags area as a field FL 21 in the memorymanagement information shown in FIG. 11 will further be described belowwith reference to FIG. 12. The volume attribute flags area is of onebyte, in which the flags at the first to eighth bits are defined asfollows:

The first bit is a “prevent write flag”, second bit is a “prevent readflag”, third bit is a “prevent write retry flag”, and the fourth bit isa “prevent read retry flag”. These flags allow and/or prevent write tothe entire volume (magnetic tape), read from the entire volume, retry towrite data based on RAW at the time of recording, and retry to read dataat the time of reproduction, respectively. They are defined such thatwhen the bit is “1”, the flag “prevents” the write, read, write retry orread retry and when the bit is “0”, the flag “allows” such operation.

The fifth, sixth and seventh bits are reserved areas.

The eighth bit is a flag to open and/or close the volume. Whilerecording is being done to the magnetic tape, “1 (open)” is set at thisbit. When the recording is complete, “0 (closed)” is set.

Next, the structure of the volume tag in the field FL3 in FIG. 8 will bedescribed below with reference to FIG. 13. The size of each data (inbytes) is shown at the right.

The “volume tag” has at the top thereof a “volume information checksum”including a checksum of “volume information”, in which basic managementinformation for the entire tape cassette is stored.

Further to the “volume information”, there is provided an “accumulativepartition information checksum” including a checksum of “accumulativepartition information”, in which history of use of the tape cassette,having been accumulated starting at the manufacture of the tape cassetteis stored.

Following the “accumulative partition”, there are provided a “volumenote checksum”, “volume note” and a “cartridge serial number”. There isstored in the “cartridge serial number” area a serial number being a32-character information based on the ASCII code for example.

The “cartridge serial number” is followed by a “manufacturer ID” inwhich a code number for the tape cassette manufacturer is stored as amanufacturer identifier.

Further, the “manufacturer ID” is followed by a “secondary ID” for thetype of the tape cassette, in which an tape attribute information isstored as a code value of one byte.

The “secondary ID” is followed by a “cartridge serial number partchecksum” including a checksum of cartridge serial number, manufacturerID and secondary ID.

The volume tag area (FL3) includes also “specific volume tags” 1 to 13each of 36 bytes as a reserved area.

Next, the structure of the “volume information” in the field FL31 inFIG. 13 will further be described below with reference to FIGS. 14 to17.

As shown in FIG. 14, the volume information area stores, in the top areaof one byte, a checksum of volume information.

The “volume information checksum” area is followed by an “eject status”of 20 bytes, “reel diameter” of 4 bytes, “initialize count” of 3 bytes,and a “volume information on tape” of 72 bytes in this order.

In the “eject status” area, there is stated information on the logicalposition of the magnetic tape 3 when the tape cassette is unloaded. Inthe “reel diameter” area, there are stated diameters of both the reelhubs 2A and 3B when the tape cassette is unloaded.

In the “initialize count” area, there is stored a number ofinitializations of the magnetic tape 3.

The volume information on tape indicated as the FL312 in FIG. 14 has acontent as in shown in FIG. 15.

As shown in FIG. 15, the “volume information on tape” includes, inaddition to reserved areas, a “super-high speed enable flag” of one bit,“system log allocation flags” of 2 bits, “always unload PBOT flag” ofone bit, “AIT native flag” of one bit, “last valid partition number” ofone byte, and “optional device area allocation map” of 32 bytes.

The “super-high speed search enable flag” indicates whether or not thetape position information stored as the absolute volume map of MIC 4 isto be utilized to validate a function to further increase the high-speedsearch.

The “system log allocation flags” indicates a location where there isstored a system log the tape streaming drive has to preferentially usefor the system log of the tape cassette.

The definition of the “system log allocation flags” will further bedescribed later.

The “always unload PBOT flag” indicates that the tape cassette is to beunloaded with the magnetic tape 3 at a device area at PBOT even if anoptional device area exists in any of multiple partitions formed on themagnetic tape 3.

The “AIT native flag” indicates the mode of the tape cassette.

The “last valid partition number” indicates the number for the lastpartition formed on the magnetic tape.

The “optional device area map” area is of 256 bits each of which is foreach of the partitions formed on the magnetic tape 3. When the bit valueis “1”, it indicates that an optional device area is formed in apartition corresponding to the bit.

The “system log allocation flags” indicated as a field FL321 a in FIG.15 will be described below.

As will be understood from the preceding and subsequent descriptions,there can be stored in MIC 4 predetermined management information(system log) including information indicating the history of use of themagnetic tape. As shown in FIGS. 6A, 6B and 6C and FIGS. 7A, 7B and 7C,the magnetic tape has formed thereon a system area in each partition, inwhich various kinds of management information can be stored. In thisembodiment, the information stored in MIC 4 has the nearly same contentas set for the system log in the system area on the magnetic tape.

As previously described with reference to FIGS. 7A, 7B and 7C, there areavailable two tape formats, mainly, the normal mode and multi-partitionmode. The tape streaming drive 10 according to the present inventionsupport both these modes.

For write or read of data to or from a tape cassette provided with MIC 4for example, reference to or updating of the system log will not be donewith respect to the system area but with respect to MIC 4 alone. Thatis, the system log stored in MIC 4 is preferentially used whether thetape cassette is formatted in the normal mode or multi-partition mode.

On the other hand, when writing or reading data to or from a tapecassette not provided with MIC 4 and which supports only the normalmode, data is written to or read from the system log area in themagnetic tape, to manage the data written or read to or from themagnetic tape.

That is, in this embodiment, the system log to preferentially be usedexists in different locations from a tape cassette provided with MIC 4to a one not provided with MIC 4.

The “system log allocation flags” is defined as identificationinformation for indicating an above-mentioned location of the system logto preferentially be used by the tape streaming drive.

FIG. 16 shows the definition of the aforementioned “system logallocation flags” (field FL312 a in FIG. 15).

As shown in FIG. 15 as well, the “system log allocation flags”information is represented by 2 bits (fourth and third bits) in apredetermined one-byte area.

As shown in FIG. 16, the fourth and third bits taking a value “0, 0”mean that the system log (management information) to preferentially beused exists in the magnetic tape alone. That is, the bits correspond toa tape cassette not provided with any MIC and which can support only thenormal mode. In this case, the “system log allocation flags” informationis recorded in a predetermined area of the system area on the magnetictape.

The fourth and third bits taking a value “1, 1” mean that the system logto preferentially be used exists in MIC alone. These bits correspond toa tape cassette provided with MIC 4.

Note that in the tape cassette provided with MIC 4, when the magnetictape is initialized for example, the value “1, 1” is set as the value ofthe fourth and third bits for the “system log allocation flags” in thesystem log in the MIC 4 and magnetic tape.

Also, the fourth and third bits taking a value “0, 1” mean that thesystem log to preferentially be used does not exist in both the magnetictape and MIC. When they are “1, 0”, the system log to preferentiallyused exists in both the magnetic tape and MIC.

Currently, however, when the fourth and third bits are “0, 1” or “1, 0”,there exist no corresponding tape cassette and format and thus thesevalues are not used in practice. That is to say, the fourth and thirdbits in the “system log allocation flags” for the tape cassette used inthis embodiment take only the values “0, 0” and “1, 1” at present.

Next, the definition of the “AIT native flag” indicated as the fieldFL312 b in FIG. 15 will further be described below with reference toFIG. 17.

As shown in FIG. 17, when the “AIT native flag” is “1”, the tapecassette supports the AIT mode. When the flag is “0”, the tape cassettesupports a DDS emulation mode.

Normally, when the magnetic tape is a fresh one not yet formatted forexample, the “AIT native flag” is defined as “0” which means that thetape cassette supports the DDS emulation mode.

The AIT mode (“1”) and DDS emulation mode (“0”) represented by the “AITnative flag” correspond to the tape formats shown in FIGS. 7A, 7B and7C.

That is, the AIT mode (“1”) indicates the multi-partition mode shown inFIG. 7C, while the DDS emulation mode (“0”) indicates the normal mode inwhich the magnetic tape is formatted to have one partition as shown inFIG. 7A or two partitions as shown in FIG. 7B.

Namely, with the “AIT native flag”, it is possible to identify in whichof the multi-partition and normal modes the magnetic tape in the tapecassette is formatted.

Next, the cell stored in the field FL4 shown in FIG. 8 will further bedescribed below.

As described in the above, the field FL4 includes the partitioninformation cell areas, user partition note cell areas, etc.

The structures of these cells are as shown in FIGS. 18A and 18B.

One cell consists of 8 bytes of link information and n bytes of data(the number of bytes varies depending upon the type of cell) as shown inFIG. 18A.

The link information of 8 bytes is provided in each cell. Its structureis shown in FIG. 18B.

The link information contains a “cell checksum” of data in the cell.

The link information contains also a “cell size” indicating the size ofthe cell.

The link information further contains a “previous cell pointer” and“next cell pointer”. These are actual linkage data (data building up alinkage structure). When a plurality of cells of the same type arelinked to each other, previous and next cells are designated with these“previous cell pointer” and “next cell pointer”, respectively.

The cells of such a structure include a partition information cell,absolute volume map information cell, user volume note cell and userpartition note cell. The partition information cell has a fixed size,and each of other cells have a variable size.

The partition information cell having a fixed size will be describedbelow with reference to FIGS. 19 and 20.

As shown in FIG. 19, the partition information cell consists of 8 bytesof link information, and 56 bytes of data as shown in FIG. 19. Eight ofthe 56 bytes of data are used as a partition memo while 48 bytes areused as partition information.

The partition information (system log) area has stored therein variouskinds of information concerning the history of magnetic tape use inpartitions to which the cells correspond. The tape streaming drive usesthe information to manage the write checksum read operation thereof.

The data structure of partition information in a partition informationcell corresponding to a cell is defined as shown in FIG. 20 for example.

The partition information cell includes a “previous groups written” areaof 4 bytes, in which there is shown information on a number of groupshaving physically been written in the above partition in the magnetictape, counted from the last updating of the partition information.

The partition information cell includes also a “total groups written”area of 4 bytes, in which there is indicated a number of groups havingever been written to the partition. The value will be cumulated untilthe service life of the tape cassette has come to end and the tapecassette cannot be used any more or is discarded.

When the tape streaming drive 10 is writing data to the magnetic tape 3,the values in these “previous groups written” and “total groups written”areas will be incremented by the system controller 15 of the tapestreaming drive correspondingly to a number of groups newly recordedwith the current recording operation.

The partition information cell includes also a “previous groups read”area of 3 bytes in which there is indicated information on a number ofgroups having physically been read, counted from the last updating ofthe partition information.

The partition information cell includes also a “total groups read” areaof 4 bytes, in which there is indicated a number of groups having everbeen read from the partition.

The partition information cell further includes a “total rewrittenframes” area of 3 bytes in which there is indicated a cumulated numberof frames to which it has been requested to rewrite data based on acommand “read-after-write (will be referred to as “RAW” hereinafter).

In the tape streaming drive according to the present invention, the RAWoperation will be such that data in a frame written to the magnetic tape3 is read by the read head 13C for example just after the write. Thedata in the frame read with the RAW operation is subject to errordetection by the system controller 15. When an error is detected in thedata, the recording system is controlled to rewrite the data in theframe where the error has occurred. The cumulative number of frames towhich data rewrite has ever been done in this way is the “totalrewritten frames”.

The partition information cell further includes a “total 3rd ECC count”area of 3 bytes, in which a cumulated number of groups in the partition,having been error-corrected using a C3 parity, is indicated.

In the tape streaming drive 10 according to the present invention, dataread from the magnetic tape 3 is error-corrected using C1, C2 and C3parities. The C3 parity is used when no data recovery can have beenattained using only the C1 and C2 parities.

Also the partition information cell includes an “access count” area of 4bytes, in which there is indicated a number of times the tape streamingdrive has accessed the partition in the magnetic tape.

Further the partition information cell includes an “update replacecount” area of 4 bytes, in which there is indicated a cumulated numberof times by which data has been rewritten (written) to the partition inthe magnetic tape by the updating. That is, the “update replace count”is a number of times the partition has been updated (data has beenwritten to the partition).

Moreover the partition information cell includes a “previous writtenframes” area of 2 bytes, in which there is indicated a number of framesin a partition to which request for data rewrite has been made, countedthe last updating of the partition information cell.

The partition information cell further includes a “previous 3rd ECCcount” area of 2 bytes, in which there is indicated a number of groupshaving been error-corrected using the C3 parity, counted from the lastupdating of the partition information.

Also the partition information cell includes a “load count” area of 3bytes, in which there is indicated a cumulated number of times the tapehas been loaded.

Note that it is standardized that serial numbers starting with #1 forexample should be assigned in an ascending order to the aforementionedframes. The serial number thus assigned are frame numbers.

The partition information cell further includes a “valid maximumabsolute frame count” area of 3 bytes, in which there is indicated acount of frames down to the last valid frame in the partition, that is,a maximum one of the frame numbers counted in the valid areas in thepartition.

The above information is consecutively rewritten as the data in thepartition is rewritten and thus the end position of the data area ischanged.

The partition information cell finally includes a “maximum absoluteframe count” area of 3 bytes, in which a count of all frames in thepartition is indicated. That is, there is indicated a last frame number(maximum) in the group of frames forming together the whole partition.

Once a partition is formed by pre-formatting for example, the aboveinformation will be a fixed value corresponding to a size (number offrames) of the partition and which will not be rewritten any longer.

Also, the partition information cell includes a “partition attributeflag” area of one byte, in which the flag at each bit has the followingcontent:

That is, the flag at the first bit is a “previous write”, the flag atthe second bit is a “prevent read”, the flag at the third bit is a“prevent write retry” and the flag at the fourth bit is a “prevent readretry”. These flags are intended to allow/prevent writing to thepartition, allow/prevent reading from the partition, allow/prevent datarewriting based on the RAW during recording, and allow/prevent data readretry during reproduction, respectively.

The fifth, sixth and seventh bits are reserved.

The flag at the eighth bit is a partition open/close flag. It is setduring recording to the partition, and reset upon completion ofrecording.

The “super-high speed search map cell” area formed at the end of thefield FL4 has a cell structure with a link information as shown in FIG.21. The information in this area is a data map necessary forimplementing the high-speed search function which makes the most of thereel motor performance without real-time acquisition of ID informationfrom the magnetic tape 3.

The high-speed search function using the super-high speed search mapcell is as follows. For example, in the course of data writing to themagnetic tape 3, logical position information is written to thehigh-speed search supporting map at every tape run over 10 m. Forsearching a file position on the magnetic tape 3, first the map ischecked and a position nearest (within 10 m) to and before the fileposition is selected which includes a sufficient margin. Since themagnetic tape thickness and reel diameters are known, the magnetic tapecan be moved by counting reel FG pulses down to the indexed position,without reading ID on the magnetic tape. That is, the magnetic tape canbe fed at such a high speed that no ID read from the magnetic tape ispossible. When the indexed position is reached with the magnetic tape 3made to run at such a high speed, the magnetic tape is slowed down to aspeed at which the ID data can be read from the magnetic tape. Thus, afile position finally designed by the host computer is searched at anordinary high speed.

The data structure in MIC 4 is as having been described with referenceto FIGS. 8 thru 21. However it should be noted that the data structurein MIC 4 is just an example. The data allocation and area setting, datacontent, data size, etc. are not limited to those having been describedin the foregoing.

5. Structure of tape cassette, which supports data format

5-1 Identification holes in tape cassette body

As having previously been described, two data formats, AIT-1 and AIT-2,have ever been standardized for the embodiment of the present invention.Actually, there are formed in each of tape cassettes write protect holescorresponding to the AIT formats the tape cassette adopts, as will bedescribed below. The tape cassette body has also formed therein anidentification hole for discrimination between data storage and otherapplication and a one for distinction from a cleaning tape cassette.Namely, the tape cassette has formed therein various identificationholes corresponding to the type thereof.

These identification holes are detected by the hole detecting mechanism26 shown in FIG. 1.

The tape cassettes usable with the tape streaming drive 10 according tothe present invention include mainly a tape cassette supporting theAIT-1 format and a tape cassette supporting the AIT-2 format,standardized for the tape streaming drive. The tape cassettes alsoincludes a cleaning tape cassette.

FIG. 22A is a bottom view of the tape cassette supporting the AIT-1 mode(will be referred to as “AIT-1 tape cassette” hereinafter). Necessaryidentification holes are formed in the bottom of the tape cassette.

As shown in FIG. 22A, the AIT-1 tape cassette has a data storageidentification hole 101 formed in the lower right portion (just abovethe terminal pins 7A to 7E) of the bottom thereof. The tape cassetteaccording to the present invention has the same external shape as theso-called “8-mm video” tape cassette. The data storage identificationhole 101, if formed open, indicates that the tape cassette is destinedfor the purpose of data storage. In other words, the data storageidentification hole 101 is formed open only in a data storage tapecassette. Even if the “8-mm video” tape cassette has the same externalshape as this tape cassette according to the present invention, the datastorage identification hole 101 is not formed in the bottom of the “8-mmvideo” tape cassette.

In the lower left portion of the tape cassette body shown in FIG. 22A,there are formed a cleaning tape cassette identification hole 102, 8-mmvideo write protect hole 103 and an AIT-1 write protect hole 104.

The cleaning tape cassette identification hole 102 is destined forjudging whether or not the tape cassette is a cleaning tape cassette. Ifthe hole is formed open, the tape cassette is a cleaning tape cassette.If the hole is closed, the tape cassette is not any cleaning tapecassette. Therefore, when the tape cassette is the AIT-1 tape cassette,the cleaning tape cassette identification hole 102 is closed.

The 8-mm video write protect hole 103 is destined for judging whether ornot writing protect function is set to prevent data write to an 8-mmvideo tape cassette. It is standardized for the AIT-1 tape cassette thatthe 8-mm video write protect hole 103 should be formed open.

The AIT-1 write protect hole 104 is intended to judge whether or not awrite protect function is set to prevent data write to the AIT-1 tapecassette.

FIG. 22B is a perspective view of the AIT-1 tape cassette with a labeledside 9 thereof being at the front.

The AIT-1 write protect hole 104 in the AIT-1 tape cassette is closableor openable correspondingly to an operation of a write protect switch110 shown in FIG. 22B. By sliding an operation tab 110 a of the writeprotect switch 110 horizontally, the AIT-1 write protect hole 104 can beopened or closed.

When the AIT-1 write protect hole 104 is open, the tape streaming drivejudges that the write protect function is set. If it is closed, thedrive judges that the write protect function is canceled (data write ispossible).

The tape cassette has also formed therein a positioning hole 106. Thishole is not any identification hole. When the tape cassette is loaded, apositioning pin will be inserted into the positioning hole 106 to securethe tape cassette to some extent.

FIG. 23A is a bottom view of a tape cassette supporting the AIT-2 mode(will be referred to as “AIT-2 tape cassette” hereinafter). FIG. 23B isa perspective view of the AIT-2 tape cassette with the labeling side 9thereof at the front. Note Note that in FIGS. 23A and 23B, the same orsimilar elements as or to those in FIGS. 22A and 22B are indicated withthe same or similar references as or to those in FIGS. 22A ans 22B andwill not further be described.

As shown in FIG. 23A, the AIT-2 tape cassette also has a data storagetape cassette identification hole 101 as in the AIT-1 tape cassette.With this identification hole 101, it can be judged that the tapecassette is a data storage tape cassette.

In the lower left portion of the tape cassette body, there is formed anAIT-2 write protect hole 105 in addition to the cleaning tape cassetteidentification hole 102, 8-mm video write protect hole 103 and an AIT-1write protect hole 104.

In the AIT-2 tape cassette as well, the cleaning tape cassetteidentification hole 102 is closed and the 8-mm video write protect hole103 is open. The AIT-1 write protect hole 104 is formed open.

The AIT-2 write protect hole 105 is intended to judge whether or not awrite protect function is set to prevent data writing to the AIT-2 tapecassette. The AIT-2 write protect hole 105 is closed or openedcorrespondingly to an operation of the write protect switch 110 shown inFIG. 23B.

The operation tab 110 a of the write protect switch 110 on the AIT-2tape cassette is adapted to be slid vertically because of itsgeometrical relation with the AIT-2 write protect hole 105. By slidingthe operation tab 101 a, the AIT-2 write protect hole 105 can be openedor closed. When the AIT-2 write protect hole 105 is open, the tapestreaming drive judges that the write protect function is set. If it isclosed, the drive judges that the write protect function is canceled.

FIGS. 24A and 24B schematically illustrate the write protect switch 110on the AIT-2 tape cassette and an example of the interlocking mechanismto open and close the AIT-2 write protect hole 105. FIGS. 24A and 24Bare sectional views of a portion of the tape cassette body where thewrite protect switch 110 is provided, when the switch 110 is in theposition shown in FIG. 23B. The write protect switch 110 is formed froma synthetic resin for example.

As shown in FIG. 24A, the write protect switch 110 consists of a slider120 which is slidable up and down as the operation tab 110 a is moved,and a projection support 123 formed integrally with the slider 120. Theslider 120 has a claw 121 which is somehow elastic. The projectionsupport 123 has formed integrally at the bottom thereof a hole fillingprojection 122 shaped correspondingly to the AIT-2 write protect hole105.

As shown in FIG. 24A, when the operation tab 110 a is moved to the upperposition, the claw 121 is engaged in a claw receiver 131. Thus the holefilling projection 122 is retained securely inside the tape cassettebody and not inserted in the AIT-2 write protect hole 105. Namely, theAIT-2 write protect hole 105 is open.

When the operation tab 110 a is moved to the lower position, the holefilling projection 122 is inserted into the AIT-2 write protect hole 105as shown in FIG. 24B. The projection 122 fills the hole 105. Namely, theAIT-2 write protect hole 105 is closed. At this time, the claw 121 isengaged in a claw receiver 132, so that the AIT-2 write protect hole 105is kept positively closed.

Thus, the AIT-2 write protect hole 105 is opened or closed dependingupon whether the AIT-2 write protect switch 110 is set at the upper orlower position.

The above data storage tape cassette identification hole 101 is detectedas will be described below with reference to FIGS. 25 and 26.

FIG. 25 shows an 8-mm video tape cassette 1A inserted by mistake intothe tape streaming drive 10 according to the present invention.

The tape streaming drive 10 is provided with a mechanism to act with thedata storage tape cassette identification hole 101 formed in a tapecassette.

As shown, the mechanism includes a positioning pin 201, for example,provided to face a due position of the positioning hole 106 formed in atape cassette and which is to be inserted into the positioning hole 106.Also, the mechanism includes an identification pin 202 shaped as shownin FIG. 25. The identification pin 202 is provided at a positionopposite to the data storage tape cassette identification hole 101 in atape cassette inserted into the tape streaming drive. Further themechanism includes a movable connector block 203 as shown. The movableconnector block 203 has connector pins 204. When a data storage tapecassette is inserted into the tape streaming drive, the connector pins204 will be put into contact with the terminal pins 7A to 7E provided onthe tape cassette.

The “8-mm video” tape cassette 1A has not formed therein the datastorage tape cassette identification hole 101 already shown in FIG. 22Aor 23B.

Therefore, when the “8-mm video” tape cassette 1A is inserted into thetape streaming drive 10 as shown in FIG. 25, the identification pin 202abuts the bottom surface of the cassette body so that the “8-mm video”tape cassette 1A will not further be movable to the appropriate loadingposition. In this case, the tape streaming drive 10 will automaticallyeject the inserted “8-mm video” tape cassette 1A by a mechanical action.

As in the above, when there is inserted into the tape streaming drive 10any tape cassette destined for other application than data storage(except for a cleaning tape cassette) such as the “8-mm video” tapecassette or a tape cassette intended for data storage but which is basedon any other standard than that on which the tape streaming driveaccording to the present invention is based, it will first be ejected bythe identification pin 202.

On the other hand, a data storage tape cassette (AIT-1 or AIT-2) can beloaded appropriately into the tape streaming drive as shown in FIG. 26.

Since the data storage tape cassette identification hole 101 is formedin a data storage tape cassette body, so when the data storage tapecassette is inserted into the tape streaming drive, the identificationpin 202 included in the above mechanism can be penetrated through thedata storage tape cassette identification hole 101, as shown in FIG. 26.As a result, the tape cassette can appropriately be loaded in the tapestreaming drive.

When the tape cassette is appropriately loaded, the positioning pin 201on the tape streaming drive 10 is penetrated through the positioninghole 106 in the tape cassette and thus positions the tape cassettecorrectly. Also the movable connector block 203 will be positioned asshown in FIG. 26 and put the connector pins 204 into contact with theterminals 7 on the tape cassette. In case the tape cassette is providedwith the contact type MIC 4B, the tape streaming drive 10 is able toaccess the contact type MIC 4B.

Also a cleaning tape cassette can appropriately be loaded as shown inFIG. 26 since it is also provided with the data storage tape cassetteidentification hole 101, which is not shown. With the tape cassette setin such a status, the cleaning tape cassette identification hole 102,8-mm video write protect hole 103, AIT-1 write protect hole 104 andAIT-2 write protect hole 105 shown in FIGS. 22A and 23A are detected bythe hole detecting mechanism 26 (not shown in FIG. 26).

5-2 Magnetic tape identification stripe

According to the present invention, the magnetic tape used in the datastorage tape cassette is adapted to identify the AIT format as will bedescribed below with reference to FIG. 27A.

FIG. 27A shows the boundary between a leader tape and magnetic tape inthe tape cassette according to the present invention. The leader tapeleads the magnetic tape for winding on the reel hub. This is anon-magnetic portion where no data can be recorded. The leader tape isprovided at either end of an entire magnetic tape. According to thepresent invention, the leader tape is so transparent as to transmitlight through it.

As shown in FIG. 27A, an identification stripe STL is provided on theleader tape near PBOT. The identification stripe STL is formed bycoloring a portion of the transparent leader tape in a predeterminedcolor so that it will not pass light through it.

The standard on the identification stripe STL is such that theidentification stripe STL should be 20.17±10.80 mm from a splice betweenthe magnetic tape and leader tape, extend over the entire width of themagnetic tape and have a width of 3.0±0.1 mm in the tape runningdirection, as shown in FIG. 27A.

The identification stripe STL is detected by the stripe sensor 26 ashown in FIG. 1. The stripe sensor 26 a is formed from a photocouplerfor example, and it detects whether or not the leader tape has thelight-opaque portion according to the above-mentioned standard. Thesystem controller 15 is adapted to detect, based on detectioninformation from the stripe sensor 26 a, whether the identificationstripe STL exists or not in the leader tape.

According to a definition shown in FIG. 27B, when the identificationstripe STL is not detected, the tape cassette is judged to support theAIT-1 mode (format). When the identification stripe STL is detected, thetape cassette is judged to support the AIT-2 or higher-order AIT mode(format).

6. Construction of tape streaming drive, which supports data format

As having been described in the foregoing, the tape streaming drive 10according to the present invention is currently adapted to support theAIT-1 and AIT-2 formats.

One of the differences in signal characteristic between the AIT-1 andAIT-2 formats is a difference in encoding method. The AIT-1 formatadopts PRML method, while the AIT-2 format adopts TCPR (Trellis partialresponse) method which is a combination of the PRML method and Trelliscoding.

Therefore, the IF/ECC controller 22 shown in FIG. 1 is actuallyconstructed as shown in FIG. 28 for example.

As shown in FIG. 28, the IF/ECC controller 22 includes an AIT-1processing block 41 and AIR-2 processing block 42.

The AIT-1 processing block 41 is provided for the AIT-1 format to encodeand demodulate data according to the'PRML method.

The AIT-2 processing block 42 is provided for the AIT-2 format to encodeand demodulate data according to the TCPR method.

There is also provided the RF processor 19 shown also in FIG. 1, and aswitch 43 is provided in the signal path between the AIT-1 and AIT-2processing blocks 41 and 42 and the RF processor 19 as shown in FIG. 28.

The switch 43 has terminals T1, T2 and T3. Any of the terminals T2 andT3 is selectively connected to the terminal T1. In this embodiment, theterminal T2 is connected to the AIT-1 processing block 41 while theterminal T3 is connected to the AIT-2 processing block 42. The terminalT1 is connected to the RF processor 19.

In this embodiment, the AIT-1 and AIT-2 processing blocks 41 and 42 areconnected at other inputs and outputs thereof to the buffer memory 23shown also in FIG. 1.

When a tape cassette loaded in the tape streaming drive is judged tohave the AIT-1 format (the operations for this judgment will further bedescribed later), the system controller 15 allows the switch 43 toconnect at the terminal T1 thereof to the terminal T2. Thus the AIT-1processing block 41 will be connected to the RF processor 19. Namely,the IF/ECC controller 22 will operate in a mode supporting the AIT-1format (namely, AIT-1 mode).

On the other hand, when the loaded tape cassette is judged to have theAIT-2 format, the system controller 15 allows the switch 43 to connectat the terminal T1 thereof to the terminal T3. In this case, the AIT-2processing block 42 will be connected to the RF processor 19, and theIF/ECC controller 22 will operate in a mode supporting the AIT-2 format(namely, AIT-2 mode).

The AIT-1 and AIT-2 formats are different from each other in recordingdensity with which data is written to the magnetic tape. It isstandardized that the AIT-2 format being a higher-order format should behigher in recording density than the AIT-1 format.

Therefore, the AIT-1 mode-oriented signal processing operations effectedin the IF/ECC controller 22 and clock frequencies used in the RFprocessor 19 and compander 21 are appropriately different from those forthe AIT-2 mode.

7. Operations to identify data format

Next, on the basis of the description having been made in the foregoing,operations effected by the system controller 15 in the tape streamingdrive 10 according to the present invention to judge the type (also dataformat) of a tape cassette used in the drive 10 will be describedherebelow with reference to FIGS. 29 to 32.

As shown in FIG. 29, after a tape cassette is inserted into a tapecassette slot of the tape streaming drive 10, the identification pin 202is used to judge the type of the tape cassette at step S101. That is, asdescribed in the above with reference to FIGS. 25 and 26, it is judgedwhich the tape cassette is, a data storage tape cassette (including acleaning tape cassette supported by the tape streaming drive 10according to the present invention) or a tape cassette for otherapplication such as an “8-mm video” tape cassette or a data storage tapecassette made by other manufacturers employing other standards than thestandard for the tape cassette according to the present invention.

If the tape cassette is judged to be for another application than thedata storage, the system controller 15 ejects the tape cassette at stepS110 and exits this routine by returning to the beginning of theprocedure.

On the other hand, when the tape cassette is judged at step S101 to be adata storage tape cassette, the system controller 15 goes to step S102.When the system controller 15 goes from step S101 to S102, the tapecassette is appropriately loaded in position in the tape streaming drive10 as previously described with reference to FIG. 26.

At step S102, it is judged, based on detection information supplied fromthe hole detecting mechanism 26 and corresponding to the cleaningcassette identification hole 102, in which state the cleaning tapecassette identification hole 102 is, open or closed.

When the cleaning tape cassette identification hole 102 is judged to beopen, the tape cassette loaded in the tape streaming drive 10 is judgedto be a cleaning tape cassette. In this case, the system controller 15goes to step S111 and makes operations for cleaning the heads with thecleaning tape in the cassette. That is, the tape streaming drive 10 isinternally set for predetermined operations for the head cleaning withthe cleaning tape cassette.

On the other hand, when the cleaning tape cassette identification hole102 is judged at step S102 to be closed, the tape cassette is judged tobe a data storage tape cassette, and the system controller 15 goes tostep S103.

At step S103, it is judged whether access to (communication with) theremote type MIC is possible or not. For this purpose, the systemcontroller 15 uses the communication circuit of the remote memory I/F 30shown in FIG. 1 to try to write to the remote type MIC.

If it is decided at step S103 that the access to (or communication with)to the remote type MIC is possible (OK), the system controller 15 willmove to step S401 in FIG. 32. When the communication is judged to beimpossible (NG), the system controller 15 will go to step S104.

When the communication with the remote type MIC is judged to beimpossible (NG), it is possible that the tape cassette is of a type notprovided with the remote type MIC 4A, it is of a type provided with theremote type MIC 4A which however is faulty or the communication circuitof the remote memory I/F 30 in the tape streaming drive 10 is faulty.

At step S104, it is checked whether or not the communication with thecontact type MIC 4B is possible. That is, data read from the contacttype MIC 4B is tried via the connector 27 shown in FIG. 1.

When the communication with the contact type MIC 4B is judged to bepossible (OK), the system controller 15 goes to step S401 in FIG. 32. Ifthe check result is NG, the system controller 15 goes to step S105.

If the communication with the contact type MIC 4B is judged to beimpossible (NG), it is possible that the tape cassette is of a type notprovided with the contact type MIC 4B, it is of a type provided with thecontact type MIC 4B which however is faulty or the pin terminal of thecontact type MIC 4B or connect 27 of the tape streaming drive 10 is inpoor contact.

Therefore, when the system controller 15 goes to step S105, it ispossible that a data storage tape cassette not provided with any MIC 4is loaded or a tape cassette provided with MIC 4 is loaded but nocommunication can be done with MIC 4 for any reason.

At step S105, the tape streaming drive 10 is internally set in the AIT-1mode corresponding to the AIT-1 format. The setting of the AIT-1 modehas already been described with reference to FIG. 28 and others forexample. Also, data read from the system area of the magnetic tape istried in the AIT-1 mode.

If the communication with MIC 4 is impossible (NG), it is possible thatthe magnetic tape is a blank tape where no data is recorded or it is amagnetic tape having been pre-formatted in any other format than AIT-1and having data recorded therein. In this case, the system controller 15will go to step S201 in FIG. 30.

On the other hand, if it has been checked at step S105 that thecommunication with MIC 4 is possible (OK), the system controller 15 willgo to step S106.

When the system controller 15 has gone to step S106, informationrecorded in the system area of the magnetic tape has been acquired. Forexample, the information in the system area of the magnetic tape is heldin the S-RAM 24. Therefore, the content of the system log in the systemarea is also held in the S-RAM 24.

At step S106, reference is made to the system log allocation flags (seeFIGS. 15 and 16) to judge in which the system log to preferentially beused is, MIC 4 or magnetic tape (system area).

When the system log allocation flags indicate MIC 4 (namely, the fourthand third bits are “1, 1”), the system controller 15 goes to step S301in FIG. 31.

At step S106, it is judged whether or not the system log allocationflags show that the system log in consideration is in MIC 4. Since ithas been checked at previous steps S103 and S104 that the communicationwith MIC 4 is impossible (NG) although the system log allocation flagsshow that the system log in consideration is in MIC 4, it can beascertained nearly positively that the tape cassette is provided withMIC 4 but the communication with MIC 4 is not possible for any reason.

On the other hand, if it is judged at step S106 that the system logallocation flags show that the system log to preferentially be used isin the magnetic tape (that is, the fourth and third bits are “0, 0”, thesystem controller 15 will go to step S107.

It will be judged at step S106 that the system log allocation flags showthat the system log in consideration is in the magnetic tape, when atape cassette not provided with MIC 4 is loaded in the tape streamingdrive. The tape cassette not provided with MIC 4, referred to herein, isa tape cassette which is not physically provided with MIC 4 or a onephysically provided with MIC 4 but for which the system log allocationflags show that the tape cassette is not logically provided with MIC 4.

In the tape streaming drive 10 according to the present invention, ifMIC 4 provided in the tape cassette is judged to be faulty (this judgingoperation will further be described later), the system log allocationflags are rewritten to show that the system log is in the magnetic tape(namely, the fourth and third bits are “0, 0”), to thereby assure atleast subsequent appropriate operations for data reading. This tapecassette is a one which has been regarded as not logically having MIC 4in the above.

Thus, a tape cassette provided with MIC 4 is handled as a one notprovided with MIC in the system log in the magnetic tape, and thushandled as a tape cassette without MIC at the host computer for example.

At step S107, it is judged by detecting the AIT native flag, shown inFIGS. 15 and 17, in the system log acquired from the magnetic tape, inwhich the magnetic tape is pre-formatted, DDS emulation mode (normalmode) or AIT mode (multi-partition mode).

If it is judged at step S107 that the magnetic tape is pre-formatted inthe DDS emulation mode (normal mode), the system controller 15 goes tostep S108.

The system controller 15 will go to step S108 when the loaded tapecassette has data recorded therein in the AIT-1 format and the magnetictape in the tape cassette has one or two partitions formed therein isthe normal mode (DDS mode).

At step S108, the system controller 15 judges that the loaded tapecassette is not physically or logically provided with MIC and themagnetic tape is pre-formatted in the AIT-1 format and normal mode.Thus, the tape streaming drive is internally set correspondingly.

One of the drive settings is to set the internal function circuit in theAIT-1 mode as having previously been described with reference to FIG.28. In this case, since the magnetic tape is pre-formatted in the normalmode (DDS mode), the DDS emulation mode is set.

When in the DDS emulation mode, the system controller 15 controls eachfunctional circuit so that the tape streaming drive 10 makes writing andreading operations correspondingly to the normal mode (one-partition ormulti-partition mode).

The operation in the DDS emulation mode is to access the partition forexample.

Since the tape streaming drive 10 is initially designed to operate inthe multi-partition mode, if a command of request for access to thepartition #0 is transmitted from the host computer 40 for example, thetape streaming drive 10 will access the top partition in the magnetictape. Similarly, if a command of request for access to the partition #1is transmitted from the host computer 40, the tape streaming drive 10will access the second top partition in the magnetic tape. With theseoperations, it is possible to appropriately access a magnetic tape withmultiple partitions as shown in FIG. 7C.

When in the DDS emulation mode, if a command for access to the partition#0 is transmitted from the host computer 40 for example, the systemcontroller 15 will make a replacement to handle the partition #0 not asthe top partition but as the second top partition, and allow the tapestreaming drive to access the magnetic tape after completion of thisreplacement. Similarly, when a command for access to the partition #1 istransmitted from the host computer, the system controller 15 will make areplacement to handle the partition #1 as the second top partition, andallow the tape streaming drive to access the magnetic tape aftercompletion of the replacement. With the above replacement effected whenin the DDS emulation mode, it is possible to appropriately access themagnetic tape correspondingly to the two-partition normal mode shown inFIG. 7B.

When in the one-partition normal mode shown in FIG. 7A, the above accessto the partition is not required since only one partition is formed inthe magnetic tape.

On the other hand, when it is judged at step S107 that the magnetic tapeis reformatted in the AIT mode, the system controller 15 goes to stepS109.

The system controller 15 will go to step S109 when the following tapecassette is loaded in the tape streaming drive.

As having previously been described, it is standardized that a tapecassette formatted in the AIT mode (multi-partition mode) is providedwith MIC 4. However, when the system controller 15 goes to step S109, ithas been judged at step S106 that the system log allocation flags showthat the system log is in the magnetic tape.

That is, the system controller 15 will go to step S109 when MIC of atape cassette loaded in the tape streaming drive 10 some time in futureand in which the data format is the AIT-1 format and tape format is theAIT mode (multi-partition mode), is judged to be faulty, the system logallocation in the magnetic tape is updated so that the system logallocation flags show that the system log is in the magnetic tape andthe tape cassette is loaded again.

At step S109, the tape cassette is judged not to logically have MIC 4,and then judged to be pre-formatted in the AIT-1 format and AIT mode(multi-partition mode). Further, the tape cassette is set as awrite-protected one. Namely, the tape cassette is regarded as aread-only one.

For the write protection, the system controller 15 will effect thefollowing operations on the assumption that of the system log in a tapecassette currently loaded in the tape streaming drive, the prevent writeflag in the volume attribute flags shown in FIG. 12 for example is setto “1” (prevent). Thus, data writing to the magnetic tape will beprevented until the magnetic tape is unloaded.

For example, when a tape cassette whose MIC is faulty is handled as aone with no MIC as in the above, only the system log in the magnetictape is updated, but not the system log in MIC, in the process ofsubsequent data writing to the magnetic tape. Therefore, there will takeplace a mismatching in content between the system log in the magnetictape and that in the MIC. For use of the MIC recovered from the failure,it should preferably be avoided that there is such a mismatching insystem log content between the magnetic tape and MIC. In case of a tapecassette pre-formatted in the multi-partition mode, access (read from orwrite to) MIC is required to write to or read from the magnetic tape.Especially during data recording, information is frequently rewrittendepending upon the process of recording, and so dependence on the normalmode is higher than that on MIC.

By setting the write protect for a tape cassette regarded as having noMIC and pre-formatted in the AIT mode (multi-partition mode) so thatonly reading from the tape cassette will be done, the system log willnot be done any longer due to recording and the discrepancy in systemlog content between the magnetic tape and MIC can be minimized.

At step S109, the tape streaming drive is also set to support the tapecassette judged as in the above. In this case, the tape cassette ishandled as a read-only one to prevent data writing thereto and variousfunctional circuits including the IF/ECC controller 22 are set to theAIT-1 mode.

At step S105 in FIG. 29, the communication with MIC 4 is judged to beimpossible (NG), it can be estimated that the loaded tape cassette has ablank tape having no data recorded therein or a magnetic tape havingdata recorded in any other data format than the AIT-1 format. In thiscase, the system controller 15 goes to step S201 in FIG. 30.

At step S201 in FIG. 30, the status, open or closed, of the AIT-1 writeprotect hole 104 in the loaded tape cassette is detected based ondetection information from the hole detecting mechanism 26. When theAIT-1 write protect hole 104 is judged to be closed, the systemcontroller 15 will go to step S209.

The system controller 15 will go to step S209 when the data read fromthe system area of the magnetic tape in the AIT-1 mode is judged at stepS105 to be impossible (NG) and the AIT-1 write protect hole 104 isclosed, namely, the write protect for the AIT-1 cassette is canceled.This will take place when the AIT-1 cassette has a blank tape.

At step S209, first the length of the tape in the tape cassette ismeasured. Actually, there is available a plurality of predeterminedtypes of AIT-1 tape cassettes having magnetic tapes different in length,namely, recording capacity, from each other. For handling the currentlyloaded tape cassette as a blank tape cassette afterwards, for example,for appropriately initializing the tape cassette, the system controller15 has to know the magnetic tape length. For this purpose, the tapelength is measured as in the following at step S209.

In the tape streaming drive 10, the magnetic tape 3 is made to run at apredetermined ordinary speed for example, the diameter of the tape reel(referring herein to a diameter including the thickness of the tapewound on the reel hub) is measured, and a tape length is calculatedbased on the measured reel diameter. Conceptually, a lateral area of themagnetic tape 3 wound on the take-up reel is added to a lateral area ofthe magnetic tape wound on the supply reel to determine a sum of thelateral areas, an area of reel hub end face is subtracted from the sum,and the result is divided by a tape thickness. Thus a tape length iscalculated.

The above concept of tape length measurement can be expressed by thefollowing arithmetic expressions: $\begin{matrix}{{Tape\_ length} = \quad \frac{{\pi \times \left( {{T\_ reel}/2} \right)^{2}} + {\pi \left( {{S\_ reel}/2} \right)}^{2} - {2\quad {\pi \left( {{Hub}/2} \right)}^{2}}}{t}} \\{= \quad {{\frac{\pi}{4t}\quad \left( {{T\_ reel}^{2} + {S\_ reel}^{2}} \right)} - \frac{\pi \times {Hub}^{2}}{2t}}} \\{= \quad {{\frac{\pi}{4t \times \left( {0_{x}10000} \right)}\quad \left\{ {\left( {T - {{reel} \times 0_{x}100}} \right)^{2} + \left( {S - {{reel} \times 0_{x}100}} \right)^{2}} \right\}} -}} \\{\quad \frac{\pi \times {Hub}^{2}}{2t}} \\{= \quad {{\frac{\pi}{4t \times \left( {0_{x}10000} \right)}\quad \left\{ {{M\_ TR}^{2} + {M\_ SR}^{2}} \right\}} - \frac{\pi \times {Hub}^{2}}{2t}}} \\{= \quad {{{\left\{ {106 \times \left( {{{M\_ TR}^{2}/0_{x}}1000} \right)} \right\}/0_{x}}1000} +}} \\{\quad {\left\{ {106 \times \left( {{{M\_ SR}^{2}/0_{x}}100} \right)} \right\} - 54314}}\end{matrix}$

 π/4t=106

π×Hub²/2t=54314

where T_reel is a diameter of take-up reel, S_reel is a diameter ofsupply reel, Hub is a diameter of reel hub, t is a tape thickness (6.9μm to 0.5 μm), M_TR is a take-up reel diameter supplied from themechanical driver 17 (T_reel×0_(x) 100), and M-SR is a supply reeldiameter supplied from the mechanical driver 17 (S_reel×0_(x)100).

The above-mentioned tape thickness t is preset for a tape length of 170meters. According to the present invention, however, the tape thicknessis not limited to 6.9 μm to 0.5 μm but it may be any other value. Atstep S209, the tape length is measured more than once, such as twotimes, and the two measured lengths are compared with a plurality ofpredetermined kinds of tape length. When the measured tape length isjudged to be nearly coincident with any of the predetermined kinds oftape length, it is taken as the length of the tape in the tape cassette.The information of tape length thus determined is held in S-RAM 24 forexample.

Next at step S210, the currently loaded tape cassette is detected ashaving no MIC and a blank tape whose data format is the AIT-1.

Also at step S210, the operations of the internal functional circuits ofthe tape streaming drive are controlled for the AIT-1 mode based on theresult of tape cassette judgment, and the system controller 15 returnsto exit this routine. The blank tape is initialized in the AIT-1 format(data format) if necessary afterwards.

On the other hand, if the AIT-1 write protect hole 104 is judged at stepS201 to be open, the system controller 15 goes to step S202.

The system controller 15 will got to step S202 when the loaded tapecassette has not physically MIC 4, when the tape cassette has MIC 4which however is faulty and with which no communication can thus be done(NG) and a AIT cassette blank tape (write-protected AIT-1 cassette asthe case may be), or when the tape cassette is a one supporting theAIT-2 or higher-order format (including the AIT-2 tape cassette).

At step S202, the system controller 15 controls the tape streaming driveto detect the identification stripe STL on the leader tape havingpreviously been described with reference to FIGS. 27A and 27B in orderto judge which the tape cassette is, AIT-1 cassette or AIT-2 cassette(or an AIT cassette supporting the AIT-2 or higher-order format).

To this end, the system controller 15 has the magnetic tape run to theleader tape near PBOT until the leader tape with an identificationstripe STL formed thereon goes out of the tape cassette to a positionwhere the identification stripe STL can be detected by the stripe sensor26 a. Then the system controller 15 acquires detection informationoutput from the stripe sensor 26 a.

At step S202, when it is judged based on the detection information fromthe stripe sensor 26 a that the leader tape has no identification stripeSTL, the tape cassette will be judged to be a write-protected AIT-1cassette containing a blank tape. Thus the system controller 15 will goto step S209 having already been described.

On the other hand, when it is judged at step S202 that the leader tapehas the identification stripe STL, the tape cassette is estimated to bea tape cassette supporting the AIT-2 or higher data format.

In this case, the system controller 15 goes to step S203 where it willset the AIT-2 mode or a higher-order mode such as AIT-3, AIT-4, . . . orthe like for the internal functional circuits and check the system areaof the magnetic tape when in each of the modes. Currently, the tapestreaming drive 10 according to the present invention is designed tosupport the AIT-1 and AIT-2 modes. However, the tape streaming drive 10can be designed to support any higher data format than the AIT-2 dataformat.

If the magnetic tape has data recorded therein in a higher data formatthan the AIT-2, the system area can be read when the tape cassette hasbeen checked with a data format AIT-X (X≧2) set. It is judged that dataread from the system area is possible (OK), and the system controller 15will go to step S204.

On the other hand, if it is judged at step S203 that data read from thesystem area is not possible (NG), namely, that data read has not beenmade from the magnetic tape in any AIT mode the tape streaming drive 10can support, the system controller 15 will got to step S211.

When it is judged at step S203 that data read from the tape cassette isnot possible (NG), it is considered that the tape cassette is an AIT-2or higher-order tape cassette containing a blank tape or a tape cassettecontaining a magnetic tape in which data is recorded in a data formatthe tape streaming drive 10 according to the present invention cannotsupport. In this case, the system controller 15 goes to step S211 whereit will control to eject the currently loaded tape cassette and returnto exit this routine.

If the system controller 15 has gone to step S204 via step S203 havingbeen described in the above, it will be judged at step S204 byreferencing to the system log area in the tape system log informationacquired at step S203 in which the system log to preferentially be usedis, the magnetic tape or MIC 4.

When it is judged that the system log to preferentially be used existsin MIC 4, the system controller 15 goes to step S301 in FIG. 31. If itis judged that the system log is in the magnetic tape, the systemcontroller 15 goes to step S205.

At step S205, an AIT native flag is detected in the system log acquiredfrom the magnetic tape to judge in which the magnetic tape has beenpre-formatted, DDS emulation mode (normal mode) or AIT mode(multi-partition mode).

When it is judged that the magnetic tape has been pre-formatted in theDDS emulation mode (normal mode), the system controller 15 goes to stepS206 at which it will be judged that data has been written in themagnetic tape in the AIT-X (X≧2) in which, it has been detected at stepS203, the system area can be read (OK) and the tape cassette has thetape initially formatted in the one- or two-partition normal mode (DDSmode) and no MIC 4.

Correspondingly, the AIT-X mode and also DDS emulation mode are set forthe predetermined functional circuits in the tape streaming drive.

If it is judged at step S205 that the magnetic tape has beenpre-formatted in the AIT mode, the system controller 15 goes to stepS207.

At step S207, it will be judged whether data has been recorded in thetape cassette in a predetermined higher-order format than AIT-2 and hasmultiple partitions.

As having previously been described, however, the AIT mode(multi-partition mode) can only be supported by a tape cassette providedwith MIC 4. Therefore, the tape cassette judged to meet the base ofjudgment at step S207 is a one capable of supporting the AIT-2 orhigher-order data format, whose MIC has been judged to be faulty whenthe tape cassette is loaded some time in the future, and system logallocation flags have been rewritten to show the corresponding contentof the magnetic tape.

Thus at step S207, the data format of the tape cassette is judged atstep S203 to be a predetermined data format AIT-X higher than the AIT-2and have a magnetic tape having been formatted in the multi-partitionmode. Also in this case, the magnetic tape will be handled as alogically write-protected one on the basis having been describedconcerning step S109 in the foregoing.

The functional circuits in the tape streaming drive will be set in apredetermined AIT-X mode corresponding to the result of checking at stepS203, and the tape streaming drive be internally set to prevent writingto the magnetic tape.

At step S106 in FIG. 29 and step S204 in FIG. 30, if it is judged thatthe system log allocation flags show that the system log exists in MIC4, it will be estimated that the tape cassette is an AIT one providedwith MIC 4 with which however no communication can be done for anyreason.

If the MIC provided in the tape cassette is a remote type one, access toMIC cannot be recovered. However, when the MIC is a contact type, it ispossible to recover the access to MIC by retrying access to the MIC if apoor contact of the MIC contact has caused the communication to beimpossible.

If it is judged at step S106 or step S204 that the system log allocationflags show that the system log is in MIC 4, the system controller 15goes to step S301 in FIG. 31 where the access to the contact type MIC 4Bis retried as will further be described below.

At step S301, a variable n indicative of a number of retries is set n=1and next at step S302, a control is made for the access-retryingoperation. For example, the tape cassette supporting mechanism isslightly moved to recover a contact connection between the MIC 4B andtape streaming drive 10.

Next at step S303, write to the contact type MIC 4B is checked. When thecommunication is possible (OK), the system controller 15 goes to stepS401 in FIG. 32. On the other hand, if the communication is not possible(NG), the system controller 15 will go to step S304 at which thevariable n is incremented to n=n+1. Next, if it is judged at step S305that the variable n has not yet reached n=5, the system controller 15goes back to step S302 where the access to the contact type MIC 4B isretried. That is, the access is retried a maximum of 5 times. Note thatthis number of retries is just an example and it may freely be set.

If write to the contact type MIC 4B is impossible (NG) even with thefive retries, the system controller 15 will go to step S306.

At step S306, it is judged in which mode the magnetic tape has beenpre-formatted, DDS emulation mode (normal mode) or AIT mode(multi-partition mode), by effecting the operation at step S105 or S203to detect an AIT native flag in the system log acquired from themagnetic tape.

If it is judged that the magnetic tape has been pre-formatted in the DDSemulation mode (normal mode), the system controller 15 goes to stepS307.

At step S307, the MIC is judged to be faulty and internal functionalcircuits in the tape streaming drive are set on the assumption that noMIC logically exists. That is, as having previously been described, thesystem log allocation flags in the system log in the magnetic tape arerewritten to show that the system log to preferentially be used existsin the magnetic tape (fourth and third bits are “0, 0”).

Next at step S308, for judgement of the tape cassette type (data format)and tape format, it is first judged via which step S308 has beenreached, step S106 or S204.

If step S308 has been reached via step S106, the tape cassette inconsideration is an AIT-1 tape cassette. Therefore, the systemcontroller 15 will proceed to step S108 at which data and tape formatsof the tape cassette are judged and tape streaming drive is internallyset accordingly.

On the other hand, if the system controller 15 has reached step S308 viastep S204, the tape cassette in consideration is an AIT tape cassettesupporting a AIT-2 or higher-order data format. In this case, the systemcontroller 15 will proceed to step S206 at which the data and tapeformats of the tape cassette are judged and tape streaming drive isinternally set accordingly.

In this case, at step S108 and S206, the tape cassette will be handledas not logically having MIC, based on the system log allocation flagsset at step S307.

On the other hand, if it is judged that the tape cassette has a magnetictape having been pre-formatted in the AIT mode, the system controller 15will go to step S309.

At step S309, it is judged as at step S308 via which step S309 has beenreached, step S106 or S204.

When it is judged that step S309 has been reached via step S106, thesystem controller 15 will got to step S109. On the other hand, if it isjudged that step S309 has been reached via step S204, the systemcontroller 15 will got to step S207 at which as having previously beenmentioned, the tape cassette is judged concerning its data and tapeformats and the tape streaming drive is internally set according to theresult of judgment.

If it has been judged at step S103 or S104 in FIG. 29 that thecommunication with MIC 4 is possible (OK), or when it has been judged atstep S303 in FIG. 31 that the communication with the contact type MIC 4Bis possible (OK), the system controller 15 goes to step S401 in FIG. 32.

At step S401, the MIC type shown in FIGS. 9 and 10 is detected in thesystem log stored in MIC 4.

Actually, S-RAM 24 holds the information (system log) in MIC 4 since thewrite to MIC 4 is judged possible (OK) at step S103, S104 or S303.Subsequently, access is possible to the MIC system log stored in S-RAM24. For example, when data is written to or read from the tape cassetteloaded in the tape streaming drive, the system log stored in S-RAM 24 isfirst updated correspondingly to the result of the data write or read.The system log is updated to latest information by storing the contentof system log into MIC in the tape cassette at a predeterminedsubsequent time.

Thus, for detecting the MIC type at step S401, the MIC type may be readdirectly from MIC 4. Actually, however, it suffices to read it by accessto the MIC type area in the system log held in S-RAM 24.

By detecting the MIC type as shown in FIG. 10, an AIT-X (X≧1) format thetape cassette has to support is identified based on the seventh tofourth bits of the detected MIC type.

At next step S402, the mode of operation of the tape streaming drive 10is set to AIT-X mode according to the MIC type detected at step S401,namely, the AIT-X (X≧1) format.

Next at step S403, the system area of the magnetic tape is checked in anAIT-X mode set at step S402. If it is judged that data write isimpossible (NG), the system controller 15 will got to step S411.

At step S411, it is judged that the loaded cassette is provided with MICand has a magnetic tape having been formatted in the AIT-X format andwhich is a blank one, and the system controller 15 will return.

If the result of check at step S403 is that the data write is possible(OK), the system controller 15 goes to step S404 at which the system logallocation flags in the system log acquired from the magnetic tape aredetected. If the system log to preferentially be used is judged to be inMIC, the system controller 15 goes to step S405. On the other hand, ifit is judged the system log to preferentially be used is in the magnetictape, the system controller 15 will go to step S408.

At step S405, the AIT native flag is detected in the system log acquiredfrom the magnetic tape. When the result of checking shows that themagnetic tape has been formatted in the DDS mode (normal mode), thesystem controller 15 goes to step S406. If the result of checking isthat the tape format is the AIT mode (multi-partition mode), the systemcontroller 15 will go to step S407.

At step S406, it is judged that the tape cassette is provided with MICand having a magnetic tape having data recorded therein in the AIT-Xformat and having been formatted in the DDS mode (normal mode), and thesystem controller 15 returns. In this case, the tape streaming drive isset to the DDS emulation mode.

If the result of detection at step S405 is that the tape format is anAIT mode (multi-partition mode), the system controller 15 goes to stepS407 at which it will judge that the tape cassette is a one providedwith MIC and contains a magnetic tape having data recorded therein inthe AIT-X format and having been formatted in then AIT mode(multi-partition mode), and the returns. At this time, the tapestreaming drive is internally set to a mode of operation for themulti-partition mode.

If the system controller 15 judges based on the system log allocationflags that the system log to preferentially be used exists in themagnetic tape, which is the result of checking at step S404, it will goto step S408. The system controller 15 will go from step S404 to S408when the tape cassette is loaded some time in the future, the MIC in thetape cassette will be judged to be faulty and the system log allocationflags of the magnetic tape are rewritten to show that the system log topreferentially be used exists in the magnetic tape.

At step S408, the system controller 15 will detect as at step S405 theAIT native flag in the system log acquired from the magnetic tape. Ifthe result of detection shows that the tape cassette contains a magnetictape having been formatted in the DDS mode (normal mode), the systemcontroller 15 goes to step S409. When the result of detection is thatthe tape has been formatted in the AIT mode (multi-partition mode), thesystem controller 15 goes to step S410.

At step S409, the system controller 15 judges that the tape cassette isprovided with MIC and contains a magnetic tape having data recordedtherein in the AIT-X format and having been formatted in the DDS mode(normal mode).

The tape cassette is judged to have no MIC although the communicationwith MIC has been judged to be possible (OK), for the tape cassette hasbeen judged at the time of loading to have MIC 4 which however isfaulty. For example, with a tape cassette provided with MIC which hasbeen judged even once to be faulty, poor contact or the like will recurin the course of an access to MIC for example so that the communicationwith MIC 4 will be disabled. Also, when MIC has ever been judged to befaulty and access to MIC 4 has be prevented, it is highly possible thatthe system log in MIC 4 is incorrect since the system log has beenrewritten only in the magnetic tape in the course of a data write orread. Taking this in consideration, the tape cassette is not handled asa one with MIC from the beginning but it is handled as a one with noMIC, so that subsequent data written and read and data management can bedone appropriately.

Note that the tape streaming drive will be set at step S409 to the DDSemulation mode.

At step S410, the system controller 15 will set the AIT-X format as dataformat, and AIT mode (multi-partition mode) as tape format. Also at thistime, it is assumed in the system controller 15 that the prevent writeflag of the volume attributes flag shown in FIG. 12 is set to “1”(prevent) so that the tape cassette will be treated as a write-protectedone.

Also when the system controller 15 has reached this step S410 via stepS404, the tape cassette has been judged at the time of loading to be aone with MIC 4 which however is faulty. Therefore, it is highly probablethat MIC will be faulty during a subsequent data write. To avoid this,the data write to the magnetic tape is disabled also at step S410 whiledata read is enabled, thereby assuring appropriate operations for thedata read which is low in dependence upon MIC.

In the foregoing, the operations for judgement of the data format andtape format of a loaded tape cassette have been described with referenceto FIGS. 29 to 32. Normally, however, so long as communication with MIC4 can be done normally, the tape cassette type can be judged with theoperations at steps S101 to S104 in FIG. 29 and operations shown in FIG.32. That is to say, if only an information write to MIC 4 is possible,at least the data format of the tape on cassette can be judged byidentifying the MIC type in MIC 4.

Also, the embodiment of the present invention has been described in theforegoing concerning a tape streaming drive using as a recording mediumthe “8-mm video” tape cassette. However, it should be noted that thepresent invention is applicable to a system including a tape cassetteand tape streaming drive conforming to any other standard so far as thecassette encasing a tape-shaped recording medium is provided with amemory element capable of storing defined management information.

INDUSTRIAL APPLICABILITY

As having been described in the foregoing, the recording mediumaccording to the present invention is a tape cassette provided with amemory (MIC) to store a system log (management information) according towhich data is written to and read from a magnetic tape contained in thecassette, with the memory storing data format identification information(MIC type) indicative of a data format which the tape cassette cansupport.

With the tape drive according to the present invention, it is possibleto detect identification information (MIC type) stored in the memory(MIC) provided in a loaded tape cassette, to thereby identify the dataformat the tape cassette can support. The tape drive is internally setto operate in a mode corresponding to a data format thus identified, forexample.

For example, in case a detection hole is formed in the tape cassette toidentify the data format in which each tape cassette has data recordedtherein, if the data format type is increased in number as the dataformat is extended, more detection holes have to be formed in the tapecassette and also the hole detecting mechanism in the tape drive willunavoidably be complicated accordingly. That is, it is difficult toaccommodate the future extension data format.

According to the present invention, however, an increased number of dataformat types can easily be accommodated by storing in the memory (MIC)identification information with which the data format is identified. anda tape streaming drive.

What is claimed is:
 1. A recording medium comprising: a magnetic tape; acassette encasing the magnetic tape; and a memory provided in thecassette to store management information for management of data writtento and read from the magnetic tape; wherein the magnetic of tapeaccommodates a data format for data written to and read from themagnetic tape magnetic tape and which corresponds to any of a pluralityof predetermined data formats; and wherein the memory includes a storagearea for storage of data format identification information indicative ofthe data format of the data written to and read from the magnetic tape,wherein the memory is provided with transmission and reception means fornon-contact transfer of an information signal.
 2. The recording mediumas set forth in claim 1, wherein the memory is provided with terminalsfor transfer of information signals and said terminals face an outsideof the cassette.
 3. The recording medium as set forth in claim 1,wherein the magnetic tape has an area where an information signal isrecorded, with the area divided into at least three partitions.
 4. Therecording medium as set forth in claim 1, wherein system log allocationflags included in data format identification information recorded in themagnetic tape indicate that data format identification information isrecorded in the magnetic tape, so that the data format identificationinformation is read from the magnetic tape when the data formatidentification information cannot be read from the memory.
 5. A recordedmedium comprising: a magnetic tape; a cassette encasing the magnetictape; and a memory provided in the cassette to store managementinformation for management of data written to and read from the magnetictape, wherein the magnetic tape accommodates a data format for datawritten to and read from the magnetic tape and which corresponds to anyof a plurality of predetermined data formats, wherein the memoryincludes a storage area for storage of data format identificationinformation indicative of the data format of the data written to andread from the magnetic tape, wherein system log allocation flagsincluded in data format identification information recorded in themagnetic tape indicate that data format identification information isrecorded in the magnetic tape, so that the data format identificationinformation is read from the magnetic tape when the data formatidentification information cannot be read from the memory, wherein it isjudged, based on a native flag included in the data formatidentification information read from the magnetic tape, whether the areaof the magnetic tape where the information signal is recorded has aformat in which the area is divided into at least three partitions andwhether the area has a format in which the area is in a normal format.6. A tape drive to write and read an information signal to and from arecording medium including a magnetic tape, a cassette encasing themagnetic tape, and a memory provided in the cassette to store managementinformation for management of data written to and read from the magnetictape, wherein the magnetic tape accommodates a data format for datawritten to and read from the magnetic tape and which corresponds to anyof a plurality of predetermined data formats, and wherein the memoryincludes a storage area for storage of data format identificationinformation indicative of the data format of the data written to andread from the magnetic tape, the tape drive comprising: tape drivingmeans for writing and reading an information signal to and from themagnetic tape in a loaded recording medium; memory reading means forreading at least the data format identification information from themanagement information stored in the memory in the loaded recordingmedium; data format identifying means for identifying, based on the dataformat identification information read by the memory reading means, adata format of the loaded recording medium; controlling means forcontrolling the data driving means, wherein the tape driving meanswrites and reads the information signal in a data format selected fromat least two of the plurality of predetermined data formats, and whereinthe controlling means allows the tape driving means to write and read inthe data format identified by the data format identifying means; and ahole detecting mechanism to detect whether a cleaning cassetteidentification hole is formed in the cassette, wherein whether theloaded recording medium is a cleaning cassette is based on a result ofdetection of the cleaning cassette identification hole by the holedetecting mechanism, and when the recording medium is judged to be thecleaning cassette, a mode of operation in which the cleaning cassette isused is operated, while when the recording medium is judged not to bethe cleaning cassette, the memory reading means reads the data formatidentification information from the memory and it is judged whether thememory is provided with terminals for transfer of the information signaland whether the memory is provided with transmitting and reception meansfor non-contact transfer of the information signal.
 7. A tape drive towrite and read an information signal to and from a recording mediumincluding a magnetic tape, a cassette encasing the magnetic tape, and amemory provided in the cassette to store management information formanagement of data written to and read from the magnetic tape, whereinthe magnetic tape accommodates a data format for data written to andread from the magnetic tape and which corresponds to any of a pluralityof predetermined data formats, and wherein the memory includes a storagearea for storage of data format identification information indicative ofthe data format of the data written to and read from the magnetic tape,the tape drive comprising: tape driving means for writing and reading aninformation signal to and from the magnetic tape in a loaded recordingmedium; memory reading means for reading at least the data formatidentification information from the management information stored in thememory in the loaded recording medium; data format identifying means foridentifying, based on the data format identification information read bythe memory reading means, a data format of the loaded recording medium;controlling means for controlling the data driving means, wherein thetape driving means writes and reads the information signal in a dataformat selected from at least two of the plurality of predetermined dataformats, and wherein the controlling means allows the tape driving meansto write and read in the data format identified by the data formatidentifying means, wherein when the data format identificationinformation cannot be read from the memory, the data formatidentification information is read from the magnetic tape when systemlog allocation flags included in the data format identificationinformation read from the magnetic tape show that the data formatidentification information is recorded in the magnetic tape, based onwhether a native flag included in the data format identificationinformation read from the magnetic tape indicates whether the area ofthe recording medium where the information signal is recorded is dividedinto at least three partitions and whether the area is in a normalformat, and when it is judged that the area of the magnetic tape inwhich the information signal is recorded is divided into at least threepartitions, the memory is regarded as faulty and the magnetic tape isused as a read-only magnetic tape with prevention of the informationsignal from being written to the magnetic tape, while when it is judgedthat the magnetic tape area in which the information signal is recordedis in the normal format, the recording medium is regarded as notprovided with memory.
 8. A tape drive to write and read an informationsignal to and from a recording medium including a magnetic tape, acassette encasing the magnetic tape, and a memory provided in thecassette to store management information for management of data writtento and read from the magnetic tape, wherein the magnetic tapeaccommodates a data format for data written to and read from themagnetic tape and which corresponds to any of a plurality ofpredetermined data formats, and wherein the memory includes a storagearea for storage of data format identification information indicative ofthe data format of the data written to and read from the magnetic tape,the tape drive comprising: tape driving means for writing and reading aninformation signal to and from the magnetic tape in a loaded recordingmedium; memory reading means for reading at least the data formatidentification information from the management information stored in thememory in the loaded recording medium; data format identifying means foridentifying, based on the data format identification information read bythe memory reading means, a data format of the loaded recording medium;controlling means for controlling the data driving means, wherein thetape driving means writes and reads the information signal in a dataformat selected from at least two of the plurality of predetermined dataformats, and wherein the controlling means allows the tape driving meansto write and read in the data format identified by the data formatidentifying means; a hole detecting mechanism for detecting whether awrite protect hole preventing writing of the information signal isformed in the cassette; and a stripe sensor for optically detecting anidentification stripe formed on the magnetic tape; wherein when the dataformat identification information cannot be read from the memory andreading data format identification information from the magnetic tape isimpossible, it is judged, based on the result of write protect holedetection, whether writing of the information signal is prevented; whilewhen it is judged that writing of the information signal is notprevented, the magnetic tape is judged to have the format in which thearea of the magnetic tape where the information signal is recorded is ina normal format; and when it is judged that writing of the informationsignal is prevented via identification of the identification stripe bythe stripe sensor; when the identification stripe is not detected, it isjudged that the memory is not provided and the area of the magnetic tapewhere the information signal is recorded has the format in which thearea is in the normal format; and when the identification stripe isdetected, reading of the data identification information from themagnetic tape is attempted.
 9. The tape drive as set forth in claim 8,wherein when it is judged that the memory is not provided and the areaof the magnetic tape where the information signal is recorded has theformat in which the area is in the normal format, the magnetic tape isconsidered a blank tape in which the information signal is not yetrecorded.
 10. A recording medium type identifying method foridentification of a data format of a recording medium to and from whichan information signal is written and read and which includes a magnetictape, a cassette encasing the magnetic tape, and a memory provided inthe cassette to store management information for management of datawritten to and read from the magnetic tape, the magnetic tape having adata format for data written to and read from the magnetic tape andwhich corresponds to one of a plurality of predetermined data formats,and the memory including a storage area for storage of data formatidentification information indicative of the data format of the datawritten to and read from the magnetic tape, the method comprising stepsof: reading at least the data format identification information from themanagement information stored in the memory in the recording medium;identifying, based on the data format identification information, a dataformat of the loaded recording medium; and detecting whether a cleaningcassette identification hole is formed in the cassette of the recordingmedium, and when it is judged based on a result of detection of thecleaning cassette identification hole that the recording medium used isnot the cleaning cassette, the data format identification information isread from the memory and it is judged whether the memory is providedwith terminals for transfer of the information signal and whether thememory is provided with transmitting and reception means for non-contacttransfer of the information signal.
 11. A recording medium typeidentifying method for identification of a data format of a recordingmedium to and from which an information signal is written and read andwhich includes a magnetic tape, a cassette encasing the magnetic tape,and a memory provided in the cassette to store management informationfor management of data written to and read from the magnetic tape, themagnetic tape having a data format for data written to and read from themagnetic tape and which corresponds to one of a plurality ofpredetermined data formats, and the memory including a storage area forstorage of data format identification information indicative of the dataformat of the data written to and read from the magnetic tape, themethod comprising steps of: reading at least the data formatidentification information from the management information stored in thememory in the recording medium; identifying, based on the data formatidentification information, a data format of the loaded recordingmedium; and wherein when the data format identification informationcannot be read from the memory, the data format identificationinformation is read from the magnetic tape when system log allocationflags included in the data format identification information read fromthe magnetic tape show that the data format identification informationread from the magnetic tape shows that the data format identificationinformation is recorded in the magnetic tape, and it is judged based ona native flag included in the data format identification informationread from the magnetic tape whether the area of the recording mediumwhere the information signal is recorded is divided into at least threepartitions and whether the area is in a normal format; when it is judgedthat the area of the magnetic tape in which the information signal isrecorded is divided into at least three partitions, the memory isregarded as being faulty and the magnetic tape is used as a read-onlymagnetic tape with the information signal prevented from being writtento the magnetic tape; and when it is judged that the magnetic tape areain which the information signal is recorded is in the normal format, therecording medium is regarded as not provided with the memory.
 12. Arecording medium type identifying method for identification of a dataformat of a recording medium to and from which an information signal iswritten and read and which includes a magnetic tape, a cassette encasingthe magnetic tape, and a memory provided in the cassette to storemanagement information for management of data written to and read fromthe magnetic tape, the magnetic tape having a data format for datawritten to and read from the magnetic tape and which corresponds to oneof a plurality of predetermined data formats, and the memory including astorage area for storage of data format identification informationindicative of the data format of the data written to and read from themagnetic tape, the method comprising steps of: reading at least the dataformat identification information from the management information storedin the memory in the recording medium; identifying, based on the dataformat identification information, a data format of the loaded recordingmedium; and when the data format identification information cannot beread from the memory and reading of the data format identificationinformation from the magnetic tape is impossible, it is judged, based ona result of write protect hole detection, whether writing of theinformation signal is prevented; wherein when it is judged that writingof the information signal is not prevented, the magnetic tape is judgedto have the area of the magnetic tape where the information signal isrecorded is in a normal format; and when it is judged that writing ofthe information signal is prevented, via identification of anidentification stripe by a stripe sensor, when the identification stripeis not detected, it is judged that the memory is not provided and thearea of the magnetic tape where the information signal is recorded is inthe normal format, and when the identification stripe is detected,reading of the data identification information from the magnetic tape isattempted.
 13. The method as set forth in claim 12, wherein when it isjudged that the memory is not provided and the area of the magnetic tapewhere the information signal is recorded is in the normal format, themagnetic tape is judged to be a blank tape in which the informationsignal is not yet recorded.